diff --git a/externs/shaka/net.js b/externs/shaka/net.js
index 44c80a6431..5fe56e7b65 100644
--- a/externs/shaka/net.js
+++ b/externs/shaka/net.js
@@ -61,6 +61,8 @@ shaka.extern.RetryParameters;
  *   licenseRequestType: ?string,
  *   sessionId: ?string,
  *   drmInfo: ?shaka.extern.DrmInfo,
+ *   initData: ?Uint8Array,
+ *   initDataType: ?string,
  *   streamDataCallback: ?function(BufferSource):!Promise
  * }}
  *
@@ -94,6 +96,12 @@ shaka.extern.RetryParameters;
  * @property {?shaka.extern.DrmInfo} drmInfo
  *   If this is a LICENSE request, this field contains the DRM info used to
  *   initialize EME.
+ * @property {?Uint8Array} initData
+ *   If this is a LICENSE request, this field contains the initData info used
+ *   to initialize EME.
+ * @property {?string} initDataType
+ *   If this is a LICENSE request, this field contains the initDataType info
+ *   used to initialize EME.
  * @property {?function(BufferSource):!Promise} streamDataCallback
  *   A callback function to handle the chunked data of the ReadableStream.
  * @exportDoc
diff --git a/lib/media/drm_engine.js b/lib/media/drm_engine.js
index 1762f5c5fe..e23aa8f7d3 100644
--- a/lib/media/drm_engine.js
+++ b/lib/media/drm_engine.js
@@ -1169,6 +1169,7 @@ shaka.media.DrmEngine = class {
 
     const metadata = {
       initData: null,
+      initDataType: null,
       loaded: false,
       oldExpiration: Infinity,
       updatePromise: null,
@@ -1245,6 +1246,7 @@ shaka.media.DrmEngine = class {
 
     const metadata = {
       initData: initData,
+      initDataType: initDataType,
       loaded: false,
       oldExpiration: Infinity,
       updatePromise: null,
@@ -1386,6 +1388,10 @@ shaka.media.DrmEngine = class {
     request.licenseRequestType = event.messageType;
     request.sessionId = session.sessionId;
     request.drmInfo = this.currentDrmInfo_;
+    if (metadata) {
+      request.initData = metadata.initData;
+      request.initDataType = metadata.initDataType;
+    }
     // NOTE: allowCrossSiteCredentials can be set in a request filter.
 
     if (shaka.media.DrmEngine.isPlayReadyKeySystem(
@@ -2342,6 +2348,7 @@ shaka.media.DrmEngine = class {
  * @typedef {{
  *   loaded: boolean,
  *   initData: Uint8Array,
+ *   initDataType: ?string,
  *   oldExpiration: number,
  *   type: string,
  *   updatePromise: shaka.util.PublicPromise
@@ -2353,6 +2360,8 @@ shaka.media.DrmEngine = class {
  *   does not mean the session is 'usable'.
  * @property {Uint8Array} initData
  *   The init data used to create the session.
+ * @property {?string} initDataType
+ *   The init data type used to create the session.
  * @property {!MediaKeySession} session
  *   The session object.
  * @property {number} oldExpiration
diff --git a/lib/net/networking_engine.js b/lib/net/networking_engine.js
index 04a7ca4265..17bf470acc 100644
--- a/lib/net/networking_engine.js
+++ b/lib/net/networking_engine.js
@@ -221,6 +221,8 @@ shaka.net.NetworkingEngine = class extends shaka.util.FakeEventTarget {
       licenseRequestType: null,
       sessionId: null,
       drmInfo: null,
+      initData: null,
+      initDataType: null,
       streamDataCallback: streamDataCallback,
     };
   }
diff --git a/test/util/cmcd_manager_unit.js b/test/util/cmcd_manager_unit.js
index 5150a36c58..b193fad640 100644
--- a/test/util/cmcd_manager_unit.js
+++ b/test/util/cmcd_manager_unit.js
@@ -124,6 +124,8 @@ describe('CmcdManager', () => {
       licenseRequestType: null,
       sessionId: null,
       drmInfo: null,
+      initData: null,
+      initDataType: null,
       streamDataCallback: null,
     };