diff --git a/src/com/echonest/api/v4/TimedEvent.java b/src/com/echonest/api/v4/TimedEvent.java
index 5962e58..b108ec6 100644
--- a/src/com/echonest/api/v4/TimedEvent.java
+++ b/src/com/echonest/api/v4/TimedEvent.java
@@ -1,10 +1,11 @@
 package com.echonest.api.v4;
 
+import java.io.Serializable;
 import java.util.Map;
 
 import com.echonest.api.v4.util.MQuery;
 
-public class TimedEvent {
+public class TimedEvent implements Serializable{
 
     private double start;
     private double duration;
diff --git a/src/com/echonest/api/v4/TrackAnalysis.java b/src/com/echonest/api/v4/TrackAnalysis.java
index 11707de..888cf03 100644
--- a/src/com/echonest/api/v4/TrackAnalysis.java
+++ b/src/com/echonest/api/v4/TrackAnalysis.java
@@ -1,11 +1,13 @@
 package com.echonest.api.v4;
 
 import com.echonest.api.v4.util.MQuery;
+
+import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 
-public class TrackAnalysis {
+public class TrackAnalysis implements Serializable{
 
     @SuppressWarnings("unchecked")
     private Map map;
diff --git a/src/com/echonest/api/v4/util/MQuery.java b/src/com/echonest/api/v4/util/MQuery.java
index a17de59..8e8d8dc 100644
--- a/src/com/echonest/api/v4/util/MQuery.java
+++ b/src/com/echonest/api/v4/util/MQuery.java
@@ -1,9 +1,10 @@
 package com.echonest.api.v4.util;
 
+import java.io.Serializable;
 import java.util.List;
 import java.util.Map;
 
-public class MQuery {
+public class MQuery implements Serializable {
 
     @SuppressWarnings("unchecked")
     private Map data;