diff --git a/cli/compilers/ts.rs b/cli/compilers/ts.rs
index 13823b24f1..34bf74ab1d 100644
--- a/cli/compilers/ts.rs
+++ b/cli/compilers/ts.rs
@@ -272,8 +272,8 @@ impl TsCompiler {
 
     let worker = TsCompiler::setup_worker(global_state.clone());
     let worker_ = worker.clone();
-    worker.post_message(req_msg).unwrap();
     let first_msg_fut = async move {
+      worker.post_message(req_msg).await.unwrap();
       let result = worker.await;
       if let Err(err) = result {
         // TODO(ry) Need to forward the error instead of exiting.
@@ -382,8 +382,8 @@ impl TsCompiler {
       .add("Compile", &module_url.to_string());
     let global_state_ = global_state.clone();
 
-    worker.post_message(req_msg).unwrap();
     let first_msg_fut = async move {
+      worker.post_message(req_msg).await.unwrap();
       let result = worker.await;
       if let Err(err) = result {
         // TODO(ry) Need to forward the error instead of exiting.
diff --git a/cli/compilers/wasm.rs b/cli/compilers/wasm.rs
index 882e28e43b..2e565dd93b 100644
--- a/cli/compilers/wasm.rs
+++ b/cli/compilers/wasm.rs
@@ -86,13 +86,14 @@ impl WasmCompiler {
     let worker_ = worker.clone();
     let url = source_file.url.clone();
 
-    let _res = worker.post_message(
-      serde_json::to_string(&base64_data)
-        .unwrap()
-        .into_boxed_str()
-        .into_boxed_bytes(),
-    );
     let fut = worker
+      .post_message(
+        serde_json::to_string(&base64_data)
+          .unwrap()
+          .into_boxed_str()
+          .into_boxed_bytes(),
+      )
+      .then(|_| worker)
       .then(move |result| {
         if let Err(err) = result {
           // TODO(ry) Need to forward the error instead of exiting.
diff --git a/cli/ops/workers.rs b/cli/ops/workers.rs
index 42f93ec573..a032905459 100644
--- a/cli/ops/workers.rs
+++ b/cli/ops/workers.rs
@@ -7,7 +7,6 @@ use crate::deno_error::ErrorKind;
 use crate::ops::json_op;
 use crate::startup_data;
 use crate::state::ThreadSafeState;
-use crate::tokio_util;
 use crate::worker::Worker;
 use deno::*;
 use futures;
@@ -20,6 +19,7 @@ use std::convert::From;
 use std::future::Future;
 use std::pin::Pin;
 use std::sync::atomic::Ordering;
+use std::sync::mpsc;
 use std::task::Context;
 use std::task::Poll;
 
@@ -153,23 +153,31 @@ fn op_create_worker(
   js_check(worker.execute(&deno_main_call));
   js_check(worker.execute("workerMain()"));
 
-  let exec_cb = move |worker: Worker| {
-    let worker_id = parent_state.add_child_worker(worker);
-    json!(worker_id)
-  };
+  let worker_id = parent_state.add_child_worker(worker.clone());
+  let response = json!(worker_id);
 
   // Has provided source code, execute immediately.
   if has_source_code {
     js_check(worker.execute(&source_code));
-    return Ok(JsonOp::Sync(exec_cb(worker)));
+    return Ok(JsonOp::Sync(response));
   }
 
-  let op = worker
+  // TODO(bartlomieju): this should spawn mod execution on separate tokio task
+  // and block on receving message on a channel or even use sync channel /shrug
+  let (sender, receiver) = mpsc::sync_channel::<Result<(), ErrBox>>(1);
+  let fut = worker
     .execute_mod_async(&module_specifier, None, false)
-    .and_then(move |()| futures::future::ok(exec_cb(worker)));
+    .then(move |result| {
+      sender.send(result).expect("Failed to send message");
+      futures::future::ok(())
+    })
+    .boxed()
+    .compat();
+  tokio::spawn(fut);
 
-  let result = tokio_util::block_on(op.boxed())?;
-  Ok(JsonOp::Sync(result))
+  let result = receiver.recv().expect("Failed to receive message");
+  result?;
+  Ok(JsonOp::Sync(response))
 }
 
 struct GetWorkerClosedFuture {
@@ -271,9 +279,10 @@ fn op_host_post_message(
   let mut table = state.workers.lock().unwrap();
   // TODO: don't return bad resource anymore
   let worker = table.get_mut(&id).ok_or_else(bad_resource)?;
-  worker
+  let fut = worker
     .post_message(msg)
-    .map_err(|e| DenoError::new(ErrorKind::Other, e.to_string()))?;
+    .map_err(|e| DenoError::new(ErrorKind::Other, e.to_string()));
+  futures::executor::block_on(fut)?;
   Ok(JsonOp::Sync(json!({})))
 }
 
diff --git a/cli/worker.rs b/cli/worker.rs
index d5cc801d86..1b931a85de 100644
--- a/cli/worker.rs
+++ b/cli/worker.rs
@@ -144,12 +144,17 @@ impl Worker {
   /// Post message to worker as a host.
   ///
   /// This method blocks current thread.
-  pub fn post_message(self: &Self, buf: Buf) -> Result<(), ErrBox> {
+  pub fn post_message(
+    self: &Self,
+    buf: Buf,
+  ) -> impl Future<Output = Result<(), ErrBox>> {
     let channels = self.external_channels.lock().unwrap();
     let mut sender = channels.sender.clone();
-    futures::executor::block_on(sender.send(buf))
-      .map(|_| ())
-      .map_err(ErrBox::from)
+    async move {
+      let result = sender.send(buf).map_err(ErrBox::from).await;
+      drop(sender);
+      result
+    }
   }
 
   /// Get message from worker as a host.
@@ -199,6 +204,7 @@ mod tests {
   use crate::startup_data;
   use crate::state::ThreadSafeState;
   use crate::tokio_util;
+  use futures::executor::block_on;
   use std::sync::atomic::Ordering;
 
   #[test]
@@ -391,11 +397,10 @@ mod tests {
 
       let msg = json!("hi").to_string().into_boxed_str().into_boxed_bytes();
 
-      let r = worker_.post_message(msg);
+      let r = block_on(worker_.post_message(msg));
       assert!(r.is_ok());
 
-      let maybe_msg =
-        futures::executor::block_on(worker_.get_message()).unwrap();
+      let maybe_msg = block_on(worker_.get_message()).unwrap();
       assert!(maybe_msg.is_some());
       // Check if message received is [1, 2, 3] in json
       assert_eq!(*maybe_msg.unwrap(), *b"[1,2,3]");
@@ -404,7 +409,7 @@ mod tests {
         .to_string()
         .into_boxed_str()
         .into_boxed_bytes();
-      let r = worker_.post_message(msg);
+      let r = block_on(worker_.post_message(msg));
       assert!(r.is_ok());
     })
   }
@@ -434,10 +439,10 @@ mod tests {
       );
 
       let msg = json!("hi").to_string().into_boxed_str().into_boxed_bytes();
-      let r = worker_.post_message(msg);
+      let r = block_on(worker_.post_message(msg));
       assert!(r.is_ok());
 
-      futures::executor::block_on(worker_future).unwrap();
+      block_on(worker_future).unwrap();
     })
   }
 
@@ -448,11 +453,8 @@ mod tests {
       let mut worker = create_test_worker();
       let module_specifier =
         ModuleSpecifier::resolve_url_or_path("does-not-exist").unwrap();
-      let result = futures::executor::block_on(worker.execute_mod_async(
-        &module_specifier,
-        None,
-        false,
-      ));
+      let result =
+        block_on(worker.execute_mod_async(&module_specifier, None, false));
       assert!(result.is_err());
     })
   }
@@ -470,11 +472,8 @@ mod tests {
         .to_owned();
       let module_specifier =
         ModuleSpecifier::resolve_url_or_path(&p.to_string_lossy()).unwrap();
-      let result = futures::executor::block_on(worker.execute_mod_async(
-        &module_specifier,
-        None,
-        false,
-      ));
+      let result =
+        block_on(worker.execute_mod_async(&module_specifier, None, false));
       assert!(result.is_ok());
     })
   }