diff --git a/tools/isobuild/package-source.js b/tools/isobuild/package-source.js
index ba135dca6b..6588f42fc7 100644
--- a/tools/isobuild/package-source.js
+++ b/tools/isobuild/package-source.js
@@ -609,8 +609,11 @@ _.extend(PackageSource.prototype, {
           } else if (key === "prodOnly") {
             self.prodOnly = !!value;
           } else {
-          // Do nothing. We might want to add some keys later, and we should err
-          // on the side of backwards compatibility.
+            // Do nothing. We might want to add some keys later, and we should err
+            // on the side of backwards compatibility.
+          }
+          if (self.debugOnly && self.prodOnly) {
+            buildmessage.error("Package can't have both debugOnly and prodOnly set.");
           }
         });
       },
diff --git a/tools/tests/package-tests.js b/tools/tests/package-tests.js
index e961990b2f..341b81a281 100644
--- a/tools/tests/package-tests.js
+++ b/tools/tests/package-tests.js
@@ -263,8 +263,7 @@ selftest.define("change packages during hot code push", [], function () {
 });
 
 // Add packages through the command line. Make sure that the correct set of
-// changes is reflected in .meteor/packages, .meteor/versions and list. Make
-// sure that debugOnly packages don't show up in production mode.
+// changes is reflected in .meteor/packages, .meteor/versions and list.
 selftest.define("add packages to app", [], function () {
   var s = new Sandbox();
   var run;
@@ -352,8 +351,18 @@ selftest.define("add packages to app", [], function () {
   run.match("no-description\n");
   run.expectEnd();
   run.expectExit(0);
+});
 
-  // Add a debugOnly package. It should work during a normal run, but print
+selftest.define("add debugOnly and prodOnly packages", [], function () {
+  var s = new Sandbox();
+  var run;
+
+  // Starting a run
+  s.createApp("myapp", "package-tests");
+  s.cd("myapp");
+  s.set("METEOR_OFFLINE_CATALOG", "t");
+
+    // Add a debugOnly package. It should work during a normal run, but print
   // nothing in production mode.
   run = s.run("add", "debug-only");
   run.match("debug-only");
@@ -389,6 +398,20 @@ selftest.define("add packages to app", [], function () {
   run.expectExit(234);
 });
 
+selftest.define("add package with both debugOnly and prodOnly", [], function () {
+  var s = new Sandbox();
+  var run;
+
+  // Add an app with a package with prodOnly and debugOnly set (an error)
+  s.createApp("myapp", "debug-only-test", {dontPrepareApp: true});
+  s.cd("myapp");
+  run = s.run("--prepare-app");
+  run.waitSecs(20);
+  run.matchErr("can't have both debugOnly and prodOnly");
+  run.expectExit(1);
+});
+
+
 // Add a package that adds files to specific client architectures.
 selftest.define("add packages client archs", function (options) {
   var runTestWithArgs = function (clientType, args, port) {