diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 3dcce593..67354670 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -3,7 +3,8 @@
 ## v0.3.0 (2021-12-22)
 
 - feat: implement `transaction` mechanism for load test
-- feat: support `--continue-on-failure` flag to continue running next step when failure occurs, default to failfast
+- feat: continue running next step when failure occurs with `--continue-on-failure` flag, default to failfast
+- feat: spawn workers with `--spawn-rate` flag
 - refactor: fork [boomer] as sub module
 - feat: report GA events with version
 - feat: run load test with the given limit and burst as rate limiter
diff --git a/internal/boomer/runner.go b/internal/boomer/runner.go
index 1a6f3c81..2ddd6f30 100644
--- a/internal/boomer/runner.go
+++ b/internal/boomer/runner.go
@@ -117,8 +117,11 @@ func (r *runner) spawnWorkers(spawnCount int, spawnRate float64, quit chan bool,
 		Msg("Spawning workers")
 
 	atomic.StoreInt32(&r.state, stateSpawning)
-	// TODO: spawn workers with spawnRate
 	for i := 1; i <= spawnCount; i++ {
+		// spawn workers with rate limit
+		sleepTime := time.Duration(1000000/r.spawnRate) * time.Microsecond
+		time.Sleep(sleepTime)
+
 		select {
 		case <-quit:
 			// quit spawning goroutine