diff --git a/twiml/voice_response.go b/twiml/voice_response.go
index fcc7e8fbb..43d5d14d1 100644
--- a/twiml/voice_response.go
+++ b/twiml/voice_response.go
@@ -362,7 +362,7 @@ func (m VoicePrompt) GetText() string {
 
 func (m VoicePrompt) GetAttr() (map[string]string, map[string]string) {
 	paramsAttr := map[string]string{
-		"For_":                  m.For_,
+		"For":                   m.For_,
 		"ErrorType":             m.ErrorType,
 		"CardType":              m.CardType,
 		"Attempt":               m.Attempt,
diff --git a/twiml/voice_response_test.go b/twiml/voice_response_test.go
index 8158ed279..5d15c7c5f 100644
--- a/twiml/voice_response_test.go
+++ b/twiml/voice_response_test.go
@@ -48,6 +48,23 @@ func TestVoice_SayVerbWithParams(t *testing.T) {
 	assert.Contains(t, resp, `language="en"`)
 }
 
+func TestVoice_PromptVerbWithParams(t *testing.T) {
+	prompt := twiml.VoicePrompt{
+		Attempt:               "1",
+		CardType:              "visa",
+		ErrorType:             "invalid-card-number",
+		For_:                  "security-code",
+		RequireMatchingInputs: "false",
+	}
+	verbs := []twiml.Element{prompt}
+	resp, _ := twiml.Messages(verbs)
+	assert.Contains(t, resp, `attempt="1"`)
+	assert.Contains(t, resp, `cardType="visa"`)
+	assert.Contains(t, resp, `errorType="invalid-card-number"`)
+	assert.Contains(t, resp, `for="security-code"`)
+	assert.Contains(t, resp, `requireMatchingInputs="false"`)
+}
+
 func TestVoice_SayVerbWithOptionalAttributes(t *testing.T) {
 	optAttrs := map[string]string{"PlaybackURL": "https://demo.twilio.com"}
 	say := twiml.VoiceSay{