diff --git a/src/constants/GITHUB_MESSAGE_SIZE_LIMIT.ts b/src/constants/GITHUB_MESSAGE_SIZE_LIMIT.ts
new file mode 100644
index 00000000..6a33a60d
--- /dev/null
+++ b/src/constants/GITHUB_MESSAGE_SIZE_LIMIT.ts
@@ -0,0 +1 @@
+export const GITHUB_MESSAGE_SIZE_LIMIT = 65535;
diff --git a/src/format/formatCoverage.ts b/src/format/formatCoverage.ts
index 828aab1a..036552a9 100644
--- a/src/format/formatCoverage.ts
+++ b/src/format/formatCoverage.ts
@@ -6,7 +6,8 @@ import { JsonReport } from '../typings/JsonReport';
 export const formatCoverage = (
     headReport: JsonReport | undefined,
     baseReport: JsonReport | undefined,
-    threshold: number | undefined
+    threshold: number | undefined,
+    hideDetails: boolean | undefined
 ): string => {
     if (headReport) {
         return getFormattedCoverage(
@@ -14,7 +15,8 @@ export const formatCoverage = (
             baseReport ? parseSummary(baseReport) : undefined,
             parseDetails(headReport),
             baseReport ? parseDetails(baseReport) : undefined,
-            threshold
+            threshold,
+            hideDetails
         );
     }
 
diff --git a/src/format/getFormattedCoverage.ts b/src/format/getFormattedCoverage.ts
index b3d68ebe..1cc740f5 100644
--- a/src/format/getFormattedCoverage.ts
+++ b/src/format/getFormattedCoverage.ts
@@ -1,17 +1,21 @@
 import { formatCoverageDetails } from './details/formatCoverageDetails';
 import { formatCoverageSummary } from './summary/formatCoverageSummary';
 import { CoverageDetailsMap, CoverageSummary } from '../typings/Coverage';
+import { i18n } from '../utils/i18n';
 
 export const getFormattedCoverage = (
     headSummary: Array<CoverageSummary>,
     baseSummary: Array<CoverageSummary> | undefined,
     headDetails: CoverageDetailsMap,
     baseDetails: CoverageDetailsMap | undefined,
-    threshold: number | undefined
+    threshold: number | undefined,
+    hideDetails: boolean | undefined
 ): string =>
     [
         formatCoverageSummary(headSummary, baseSummary, threshold),
-        formatCoverageDetails(headDetails, baseDetails, threshold),
+        !hideDetails
+            ? formatCoverageDetails(headDetails, baseDetails, threshold)
+            : `> ${i18n('detailsHidden')}`,
     ]
         .filter(Boolean)
         .join('\n');
diff --git a/src/format/strings.json b/src/format/strings.json
index 42bf58af..6f09ef3c 100644
--- a/src/format/strings.json
+++ b/src/format/strings.json
@@ -104,6 +104,7 @@
         "readingCoverageFileFailed": "Failed reading coverage file. (Error: {{ error }})",
         "failedGettingCoverage": "Getting code coverage data failed."
     },
+    "detailsHidden": ":warning: Details were not displayed: the report size has exceeded the limit." ,
     "summaryTitle": "Coverage report {{ dir }}",
     "newFilesCoverage": "Show new covered files :hatching_chick:",
     "decreasedCoverageFiles": "Show files with reduced coverage :small_red_triangle_down:",
diff --git a/src/stages/createReport.ts b/src/stages/createReport.ts
index 46fee41c..a97e84f4 100644
--- a/src/stages/createReport.ts
+++ b/src/stages/createReport.ts
@@ -1,6 +1,7 @@
 import { context } from '@actions/github';
 
 import { getReportTag } from '../constants/getReportTag';
+import { GITHUB_MESSAGE_SIZE_LIMIT } from '../constants/GITHUB_MESSAGE_SIZE_LIMIT';
 import { formatCoverage } from '../format/formatCoverage';
 import { formatErrors } from '../format/formatErrors';
 import { formatRunReport } from '../format/formatRunReport';
@@ -33,19 +34,42 @@ export const createReport = (
     const formattedErrors = formatErrors(errors);
 
     const formattedThresholdResults = formatThresholdResults(thresholdResults);
-    const coverage = formatCoverage(headReport, baseReport, undefined);
+    const coverage = formatCoverage(headReport, baseReport, undefined, false);
     const runReport: TestRunReport = {
         title: i18n(headReport.success ? 'testsSuccess' : 'testsFail'),
         summary: getTestRunSummary(headReport),
         failures: getFailureDetails(headReport),
     };
     const formattedReport = formatRunReport(runReport);
-    return {
-        text: insertArgs(template, {
+
+    let templateText = insertArgs(template, {
+        body: [
+            formattedErrors,
+            formattedThresholdResults,
+            coverage,
+            formattedReport,
+        ].join('\n'),
+        dir: workingDirectory || '',
+        tag: getReportTag(options),
+        title: insertArgs(customTitle || i18n('summaryTitle'), {
+            dir: workingDirectory ? `for \`${workingDirectory}\`` : '',
+        }),
+        sha: getSha(),
+    });
+
+    if (templateText.length > GITHUB_MESSAGE_SIZE_LIMIT) {
+        const reducedCoverage = formatCoverage(
+            headReport,
+            baseReport,
+            undefined,
+            true
+        );
+
+        templateText = insertArgs(template, {
             body: [
                 formattedErrors,
                 formattedThresholdResults,
-                coverage,
+                reducedCoverage,
                 formattedReport,
             ].join('\n'),
             dir: workingDirectory || '',
@@ -54,7 +78,11 @@ export const createReport = (
                 dir: workingDirectory ? `for \`${workingDirectory}\`` : '',
             }),
             sha: getSha(),
-        }),
+        });
+    }
+
+    return {
+        text: templateText,
         runReport,
     };
 };
diff --git a/tests/constants/GITHUB_MESSAGE_SIZE_LIMIT.test.ts b/tests/constants/GITHUB_MESSAGE_SIZE_LIMIT.test.ts
new file mode 100644
index 00000000..6ec7ea8e
--- /dev/null
+++ b/tests/constants/GITHUB_MESSAGE_SIZE_LIMIT.test.ts
@@ -0,0 +1,7 @@
+import { GITHUB_MESSAGE_SIZE_LIMIT } from '../../src/constants/GITHUB_MESSAGE_SIZE_LIMIT';
+
+describe('GITHUB_MESSAGE_SIZE_LIMIT', () => {
+    it('should be 65535', () => {
+        expect(GITHUB_MESSAGE_SIZE_LIMIT).toBe(65535);
+    });
+});
diff --git a/tests/format/__snapshots__/formatCoverage.test.ts.snap b/tests/format/__snapshots__/formatCoverage.test.ts.snap
index 8806ab86..71f51912 100644
--- a/tests/format/__snapshots__/formatCoverage.test.ts.snap
+++ b/tests/format/__snapshots__/formatCoverage.test.ts.snap
@@ -1,5 +1,15 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`formatCoverage should display warning if hiding details 1`] = `
+"| <div title=\\"Status of coverage:&#10; 🟢 - ok&#10; 🟡 - slightly more than threshold&#10; 🔴 - under the threshold\\">St.<sup>:grey_question:</sup></div> | Category   | Percentage | Covered / Total |
+| :----------------------------------------------------------------------------------------------------------------------------------------------------: | :--------- | :--------- | :-------------: |
+|                                                                           🟢                                                                           | Statements | 81.82%     |      27/33      |
+|                                                                           🟢                                                                           | Branches   | 100%       |       8/8       |
+|                                                                           🟢                                                                           | Functions  | 63.64%     |       7/11      |
+|                                                                           🟢                                                                           | Lines      | 80.65%     |      25/31      |
+> :warning: Details were not displayed: the report size has exceeded the limit."
+`;
+
 exports[`formatCoverage should format standard coverage 1`] = `
 "| <div title=\\"Status of coverage:&#10; 🟢 - ok&#10; 🟡 - slightly more than threshold&#10; 🔴 - under the threshold\\">St.<sup>:grey_question:</sup></div> | Category   | Percentage | Covered / Total |
 | :----------------------------------------------------------------------------------------------------------------------------------------------------: | :--------- | :--------- | :-------------: |
diff --git a/tests/format/formatCoverage.test.ts b/tests/format/formatCoverage.test.ts
index f1672528..0e88465e 100644
--- a/tests/format/formatCoverage.test.ts
+++ b/tests/format/formatCoverage.test.ts
@@ -3,14 +3,24 @@ import jsonReport from '../mock-data/jsonReport.json';
 
 describe('formatCoverage', () => {
     it('should format standard coverage', () => {
-        expect(formatCoverage(jsonReport, jsonReport, 0.3)).toMatchSnapshot();
-        expect(formatCoverage(jsonReport, undefined, 0.3)).toMatchSnapshot();
         expect(
-            formatCoverage(jsonReport, undefined, undefined)
+            formatCoverage(jsonReport, jsonReport, 0.3, false)
+        ).toMatchSnapshot();
+        expect(
+            formatCoverage(jsonReport, undefined, 0.3, false)
+        ).toMatchSnapshot();
+        expect(
+            formatCoverage(jsonReport, undefined, undefined, false)
+        ).toMatchSnapshot();
+    });
+
+    it('should display warning if hiding details', () => {
+        expect(
+            formatCoverage(jsonReport, jsonReport, 0.3, true)
         ).toMatchSnapshot();
     });
 
     it('should return empty string if no reports specified', () => {
-        expect(formatCoverage(undefined, undefined, 0.3)).toBe('');
+        expect(formatCoverage(undefined, undefined, 0.3, false)).toBe('');
     });
 });
diff --git a/tests/format/getFormattedCoverage.test.ts b/tests/format/getFormattedCoverage.test.ts
index 6f3d02cc..4f4f70c6 100644
--- a/tests/format/getFormattedCoverage.test.ts
+++ b/tests/format/getFormattedCoverage.test.ts
@@ -11,7 +11,8 @@ describe('getFormattedCoverage', () => {
                 undefined,
                 parseDetails(jsonReport),
                 undefined,
-                undefined
+                undefined,
+                false
             )
         ).toMatchSnapshot();
     });