diff --git a/main/Defaults.scala b/main/Defaults.scala
index e1c84b169..9cc0d692a 100644
--- a/main/Defaults.scala
+++ b/main/Defaults.scala
@@ -233,6 +233,9 @@ object Defaults extends BuildCommon
 	def watchTransitiveSourcesTask: Initialize[Task[Seq[File]]] =
 		inDependencies[Task[Seq[File]]](watchSources.task, const(std.TaskExtra.constant(Nil)), aggregate = true, includeRoot = true) apply { _.join.map(_.flatten) }
 
+	def transitiveUpdateTask: Initialize[Task[Seq[UpdateReport]]] =
+		forDependencies(ref => (update.task in ref).?, aggregate = false, includeRoot = false) apply( _.flatten.join)
+
 	def watchSetting: Initialize[Watched] = (pollInterval, thisProjectRef, watchingMessage, triggeredMessage) { (interval, base, msg, trigMsg) =>
 		new Watched {
 			val scoped = watchTransitiveSources in base
@@ -543,8 +546,11 @@ object Defaults extends BuildCommon
 	}
 
 	def inDependencies[T](key: SettingKey[T], default: ProjectRef => T, includeRoot: Boolean = true, classpath: Boolean = true, aggregate: Boolean = false): Initialize[Seq[T]] =
+		forDependencies[T,T](ref => (key in ref) ?? default(ref), includeRoot, classpath, aggregate)
+
+	def forDependencies[T,V](init: ProjectRef => Initialize[V], includeRoot: Boolean = true, classpath: Boolean = true, aggregate: Boolean = false): Initialize[Seq[V]] =
 		Project.bind( (loadedBuild, thisProjectRef).identity ) { case (lb, base) =>
-			transitiveDependencies(base, lb, includeRoot, classpath, aggregate) map ( ref => (key in ref) ?? default(ref) ) join ;
+			transitiveDependencies(base, lb, includeRoot, classpath, aggregate) map init join ;
 		}
 
 	def transitiveDependencies(base: ProjectRef, structure: LoadedBuild, includeRoot: Boolean, classpath: Boolean = true, aggregate: Boolean = false): Seq[ProjectRef] =
@@ -722,8 +728,10 @@ object Classpaths
 		},
 		ivySbt <<= ivySbt0,
 		ivyModule <<= (ivySbt, moduleSettings) map { (ivySbt, settings) => new ivySbt.Module(settings) },
-		update <<= (ivyModule, thisProjectRef, updateConfiguration, cacheDirectory, scalaInstance, streams) map { (module, ref, config, cacheDirectory, si, s) =>
-			cachedUpdate(cacheDirectory / "update", Project.display(ref), module, config, Some(si), s.log)
+		transitiveUpdate <<= transitiveUpdateTask,
+		update <<= (ivyModule, thisProjectRef, updateConfiguration, cacheDirectory, scalaInstance, transitiveUpdate, streams) map { (module, ref, config, cacheDirectory, si, reports, s) =>
+			val depsUpdated = reports.exists(!_.stats.cached)
+			cachedUpdate(cacheDirectory / "update", Project.display(ref), module, config, Some(si), depsUpdated, s.log)
 		},
 		update <<= (conflictWarning, update, streams) map { (config, report, s) => ConflictWarning(config, report, s.log); report },
 		transitiveClassifiers in GlobalScope :== Seq(SourceClassifier, DocClassifier),
@@ -798,7 +806,7 @@ object Classpaths
 		}})
 	}
 
-	def cachedUpdate(cacheFile: File, label: String, module: IvySbt#Module, config: UpdateConfiguration, scalaInstance: Option[ScalaInstance], log: Logger): UpdateReport =
+	def cachedUpdate(cacheFile: File, label: String, module: IvySbt#Module, config: UpdateConfiguration, scalaInstance: Option[ScalaInstance], depsUpdated: Boolean, log: Logger): UpdateReport =
 	{
 		implicit val updateCache = updateIC
 		implicit val updateReport = updateReportF
@@ -809,11 +817,16 @@ object Classpaths
 			log.info("Done updating.")
 			scalaInstance match { case Some(si) => substituteScalaFiles(si, r); case None => r }
 		}
+		def uptodate(inChanged: Boolean, out: UpdateReport): Boolean =
+			!depsUpdated &&
+			!inChanged &&
+			out.allFiles.forall(_.exists) &&
+			out.cachedDescriptor.exists
 
 		val f =
 			Tracked.inputChanged(cacheFile / "inputs") { (inChanged: Boolean, in: In) =>
 				val outCache = Tracked.lastOutput[In, UpdateReport](cacheFile / "output") {
-					case (_, Some(out)) if !inChanged && out.allFiles.forall(_.exists) && out.cachedDescriptor.exists => out
+					case (_, Some(out)) if uptodate(inChanged, out) => out
 					case _ => work(in)
 				}
 				outCache(in)
diff --git a/main/Keys.scala b/main/Keys.scala
index 40176de6f..ac4e3a074 100644
--- a/main/Keys.scala
+++ b/main/Keys.scala
@@ -231,6 +231,7 @@ object Keys
 	val ivySbt = TaskKey[IvySbt]("ivy-sbt", "Provides the sbt interface to Ivy.")
 	val ivyModule = TaskKey[IvySbt#Module]("ivy-module", "Provides the sbt interface to a configured Ivy module.")
 	val update = TaskKey[UpdateReport]("update", "Resolves and optionally retrieves dependencies, producing a report.")
+	val transitiveUpdate = TaskKey[Seq[UpdateReport]]("transitive-update", "UpdateReports for the internal dependencies of this project.")
 	val updateClassifiers = TaskKey[UpdateReport]("update-classifiers", "Resolves and optionally retrieves classified artifacts, such as javadocs and sources, for dependency definitions, transitively.", update)
 	val transitiveClassifiers = SettingKey[Seq[String]]("transitive-classifiers", "List of classifiers used for transitively obtaining extra artifacts for sbt or declared dependencies.")
 	val updateSbtClassifiers = TaskKey[UpdateReport]("update-sbt-classifiers", "Resolves and optionally retrieves classifiers, such as javadocs and sources, for sbt, transitively.", updateClassifiers)
diff --git a/sbt/src/sbt-test/dependency-management/invalidate-internal/changes/A.scala b/sbt/src/sbt-test/dependency-management/invalidate-internal/changes/A.scala
new file mode 100644
index 000000000..53e0bd0b5
--- /dev/null
+++ b/sbt/src/sbt-test/dependency-management/invalidate-internal/changes/A.scala
@@ -0,0 +1,3 @@
+object A {
+	def apply(x: org.junit.runners.JUnit4) = ()
+}
\ No newline at end of file
diff --git a/sbt/src/sbt-test/dependency-management/invalidate-internal/changes/b.sbt b/sbt/src/sbt-test/dependency-management/invalidate-internal/changes/b.sbt
new file mode 100644
index 000000000..6d4e04264
--- /dev/null
+++ b/sbt/src/sbt-test/dependency-management/invalidate-internal/changes/b.sbt
@@ -0,0 +1 @@
+libraryDependencies += "junit" % "junit" % "4.5"
diff --git a/sbt/src/sbt-test/dependency-management/invalidate-internal/project/P.scala b/sbt/src/sbt-test/dependency-management/invalidate-internal/project/P.scala
new file mode 100644
index 000000000..aacfc450b
--- /dev/null
+++ b/sbt/src/sbt-test/dependency-management/invalidate-internal/project/P.scala
@@ -0,0 +1,9 @@
+import sbt._
+import Keys._
+
+object P extends Build
+{
+	lazy val root = Project("root", file("."))
+	lazy val a = Project("a", file("a")) dependsOn(b)
+	lazy val b = Project("b", file("b")) 
+}	
\ No newline at end of file
diff --git a/sbt/src/sbt-test/dependency-management/invalidate-internal/test b/sbt/src/sbt-test/dependency-management/invalidate-internal/test
new file mode 100644
index 000000000..4c8db46c9
--- /dev/null
+++ b/sbt/src/sbt-test/dependency-management/invalidate-internal/test
@@ -0,0 +1,11 @@
+> a/compile
+$ copy-file changes/A.scala a/A.scala
+-> a/compile
+
+$ copy-file changes/b.sbt b/build.sbt
+> reload
+> a/compile
+
+$ delete b/build.sbt
+> reload
+-> a/compile
\ No newline at end of file