diff --git a/tapeout/src/main/scala/transforms/retime/Retime.scala b/tapeout/src/main/scala/transforms/retime/Retime.scala
new file mode 100644
index 00000000..0f67adea
--- /dev/null
+++ b/tapeout/src/main/scala/transforms/retime/Retime.scala
@@ -0,0 +1,45 @@
+// See LICENSE for license details.
+
+package barstools.tapeout.transforms.retime
+
+import chisel3.internal.InstanceId
+import firrtl.PrimOps.Not
+import firrtl.annotations.{Annotation, CircuitName, ModuleName, Named, ComponentName}
+import firrtl.ir.{Input, UIntType, IntWidth, Module, Port, DefNode, NoInfo, Reference, DoPrim, Block, Circuit}
+import firrtl.passes.Pass
+import firrtl.{CircuitForm, CircuitState, LowForm, Transform}
+
+object RetimeAnnotation {
+  def apply(target: ModuleName): Annotation = Annotation(target, classOf[RetimeTransform], "retime")
+  def unapply(a: Annotation): Option[Named] = a match {
+    case Annotation(m, t, "retime") if t == classOf[RetimeTransform] => Some(m)
+    case _ => None
+  }
+}
+
+class RetimeTransform extends Transform {
+  override def inputForm: CircuitForm = LowForm
+  override def outputForm: CircuitForm = LowForm
+
+  override def execute(state: CircuitState): CircuitState = {
+    getMyAnnotations(state) match {
+      case Nil => state
+      case seq => seq.foreach {
+        case RetimeAnnotation(ModuleName(module, CircuitName(_))) =>
+          logger.info(s"Retiming module $module")
+        case RetimeAnnotation(ComponentName(name, ModuleName(module, CircuitName(_)))) =>
+          logger.info(s"Retiming instance $module.$name")
+        case _ =>
+          throw new Exception(s"There should be RetimeAnnotations, got ${seq.mkString(" -- ")}")
+      }
+      state
+    }
+  }
+}
+
+trait RetimeLib {
+  self: chisel3.Module =>
+  def retime(component: InstanceId): Unit = {
+    annotate(chisel3.experimental.ChiselAnnotation(component, classOf[RetimeTransform], "retime"))
+  }
+}
diff --git a/tapeout/src/test/scala/transforms/retime/RetimeSpec.scala b/tapeout/src/test/scala/transforms/retime/RetimeSpec.scala
new file mode 100644
index 00000000..bd52b5bc
--- /dev/null
+++ b/tapeout/src/test/scala/transforms/retime/RetimeSpec.scala
@@ -0,0 +1,71 @@
+// See LICENSE for license details.
+
+package barstools.tapeout.transforms.retime.test
+
+import chisel3._
+import firrtl._
+import org.scalatest.{FlatSpec, Matchers}
+import chisel3.experimental._
+import chisel3.util.HasBlackBoxInline
+import chisel3.iotesters._
+import barstools.tapeout.transforms.retime._
+
+class RetimeSpec extends FlatSpec with Matchers {
+  def normalized(s: String): String = {
+    require(!s.contains("\n"))
+    s.replaceAll("\\s+", " ").trim
+  }
+  def uniqueDirName[T](gen: => T, name: String): String = {
+    val genClassName = gen.getClass.getName
+    name + genClassName.hashCode.abs
+  }
+
+  behavior of "retime library"
+
+  it should "pass simple retime module annotation" in {
+    val gen = () => new RetimeModule()
+    val dir = uniqueDirName(gen, "RetimeModule")
+    chisel3.Driver.execute(Array("-td", s"test_run_dir/$dir", "-foaf", s"test_run_dir/$dir/final.anno"), gen) shouldBe a [ChiselExecutionSuccess]
+
+    val lines = io.Source.fromFile(s"test_run_dir/$dir/final.anno").getLines().map(normalized).toSeq
+    lines should contain ("Annotation(ModuleName(RetimeModule,CircuitName(RetimeModule)),class barstools.tapeout.transforms.retime.RetimeTransform,retime)")
+  }
+  
+  // TODO(azidar): need to fix/add instance annotations
+  ignore should "pass simple retime instance annotation" in {
+    val gen = () => new RetimeInstance()
+    val dir = uniqueDirName(gen, "RetimeInstance")
+    chisel3.Driver.execute(Array("-td", s"test_run_dir/$dir", "-foaf", s"test_run_dir/$dir/final.anno"), gen) shouldBe a [ChiselExecutionSuccess]
+
+    val lines = io.Source.fromFile(s"test_run_dir/$dir/final.anno").getLines().map(normalized).toSeq
+    lines should contain ("Annotation(ComponentName(instance, ModuleName(RetimeInstance,CircuitName(RetimeInstance))),class barstools.tapeout.transforms.retime.RetimeTransform,retime)")
+  }
+}
+
+class RetimeModule extends Module with RetimeLib {
+  val io = IO(new Bundle {
+    val in = Input(UInt(15.W))
+    val out = Output(UInt(15.W))
+  })
+  io.out := io.in
+  retime(this)
+}
+
+class MyModule extends Module with RetimeLib {
+  val io = IO(new Bundle {
+    val in = Input(UInt(15.W))
+    val out = Output(UInt(15.W))
+  })
+  io.out := io.in
+}
+
+class RetimeInstance extends Module with RetimeLib {
+  val io = IO(new Bundle {
+    val in = Input(UInt(15.W))
+    val out = Output(UInt(15.W))
+  })
+  val instance = Module(new MyModule)
+  retime(instance)
+  instance.io.in := io.in
+  io.out := instance.io.out
+}