diff --git a/packages/accounts-base/accounts_server.js b/packages/accounts-base/accounts_server.js
index a828a87c4b..058cb6d66a 100644
--- a/packages/accounts-base/accounts_server.js
+++ b/packages/accounts-base/accounts_server.js
@@ -177,23 +177,23 @@ Accounts._getLoginToken = function (methodInvocation) {
 Accounts._setLoginToken = function (methodInvocation, newToken) {
   var oldToken = methodInvocation._sessionData.loginToken;
   methodInvocation._sessionData.loginToken = newToken;
-  loginTokenChanged(methodInvocation.sessionId, newToken, oldToken);
+  loginTokenChanged(methodInvocation.session.id, newToken, oldToken);
 };
 
 
 // sessionId -> SessionHandle
-// XXX Wouldn't be necessary if there was an API to get the session or
-// session handle from a session id.
-var sessionHandles = {};
+// XXX Wouldn't be necessary if there was an API to get the session
+// from a session id via Meteor.server.sessions[sessionId].sessionHandle
+var sessions = {};
 
-Meteor.server.onConnection(function (sessionHandle) {
-  var sessionId = sessionHandle.id;
-  sessionHandles[sessionId] = sessionHandle;
-  sessionHandle.onClose(function () {
-    var token = sessionHandle._sessionData.loginToken;
+Meteor.server.onConnection(function (session) {
+  var sessionId = session.id;
+  sessions[sessionId] = session;
+  session.onClose(function () {
+    var token = session._sessionData.loginToken;
     if (token)
       removeSessionFromToken(token, sessionId);
-    delete sessionHandles[sessionId];
+    delete sessions[sessionId];
   });
 });
 
@@ -205,7 +205,7 @@ var closeSessionsForTokens = function (tokens) {
   _.each(tokens, function (token) {
     if (_.has(sessionsByLoginToken, token)) {
       _.each(sessionsByLoginToken[token], function (sessionId) {
-        sessionHandles[sessionId] && sessionHandles[sessionId].close();
+        sessions[sessionId] && sessions[sessionId].close();
       });
     }
   });
diff --git a/packages/livedata/livedata_common.js b/packages/livedata/livedata_common.js
index 147e85f8ba..fda4a32437 100644
--- a/packages/livedata/livedata_common.js
+++ b/packages/livedata/livedata_common.js
@@ -29,9 +29,8 @@ MethodInvocation = function (options) {
   // reruns subscriptions
   this._setUserId = options.setUserId || function () {};
 
-  // On the server, the session id of the connection this method call
-  // came in on.
-  this.sessionId = options.sessionId;
+  // On the server, the session this method call came in on.
+  this.session = options.session;
 
   // Scratch data scoped to this connection (livedata_connection on the
   // client, livedata_session on the server). This is only used
diff --git a/packages/livedata/livedata_server.js b/packages/livedata/livedata_server.js
index 92574d89df..45e7098fc3 100644
--- a/packages/livedata/livedata_server.js
+++ b/packages/livedata/livedata_server.js
@@ -566,7 +566,7 @@ _.extend(Session.prototype, {
         userId: self.userId,
         setUserId: setUserId,
         unblock: unblock,
-        sessionId: self.id,
+        session: self.sessionHandle,
         sessionData: self.sessionData
       });
       try {
@@ -1263,23 +1263,22 @@ _.extend(Server.prototype, {
       var setUserId = function() {
         throw new Error("Can't call setUserId on a server initiated method call");
       };
-      var sessionId = null;
+      var session = null;
       var currentInvocation = DDP._CurrentInvocation.get();
       if (currentInvocation) {
         userId = currentInvocation.userId;
         setUserId = function(userId) {
           currentInvocation.setUserId(userId);
         };
-        sessionId = currentInvocation.sessionId;
+        session = currentInvocation.session;
       }
 
       var invocation = new MethodInvocation({
         isSimulation: false,
         userId: userId,
         setUserId: setUserId,
-        sessionId: sessionId,
-        // XXX the Server object doesn't have a `sessionData` field.
-        sessionData: self.sessionData
+        session: session,
+        sessionData: session && session._sessionData
       });
       try {
         var result = DDP._CurrentInvocation.withValue(invocation, function () {
diff --git a/packages/livedata/livedata_server_tests.js b/packages/livedata/livedata_server_tests.js
index b8629f4b73..69f5dc9636 100644
--- a/packages/livedata/livedata_server_tests.js
+++ b/packages/livedata/livedata_server_tests.js
@@ -61,9 +61,9 @@ var innerCalled = null;
 
 Meteor.methods({
   livedata_server_test_inner: function () {
-    var sessionId = this.sessionId;
+    var self = this;
     Meteor.defer(function () {
-      innerCalled(sessionId);
+      innerCalled(self);
     });
   },
 
@@ -81,8 +81,8 @@ Tinytest.addAsync(
       callbackHandle.stop();
       sessionId = sessionHandle.id;
     });
-    innerCalled = function (methodSessionId) {
-      test.equal(methodSessionId, sessionId);
+    innerCalled = function (methodInvocation) {
+      test.equal(methodInvocation.session.id, sessionId);
       onComplete();
     };
     var connection = DDP.connect(Meteor.absoluteUrl());
@@ -93,15 +93,33 @@ Tinytest.addAsync(
 
 
 Tinytest.addAsync(
-  "livedata server - sessionId in nested method invocation",
+  "livedata server - session in nested method invocation",
   function (test, onComplete) {
     var sessionId;
     var callbackHandle = Meteor.server.onConnection(function (sessionHandle) {
       callbackHandle.stop();
       sessionId = sessionHandle.id;
     });
-    innerCalled = function (methodSessionId) {
-      test.equal(methodSessionId, sessionId);
+    innerCalled = function (methodInvocation) {
+      test.equal(methodInvocation.session.id, sessionId);
+      onComplete();
+    };
+    var connection = DDP.connect(Meteor.absoluteUrl());
+    connection.call('livedata_server_test_outer');
+    connection.disconnect();
+  }
+);
+
+
+Tinytest.addAsync(
+  "livedata server - session data in nested method invocation",
+  function (test, onComplete) {
+    var callbackHandle = Meteor.server.onConnection(function (session) {
+      callbackHandle.stop();
+      session._sessionData.foo = 123;
+    });
+    innerCalled = function (methodInvocation) {
+      test.equal(methodInvocation._sessionData.foo, 123);
       onComplete();
     };
     var connection = DDP.connect(Meteor.absoluteUrl());