diff --git a/alerts.go b/alerts.go
index 228b27e..2b44d51 100644
--- a/alerts.go
+++ b/alerts.go
@@ -42,6 +42,7 @@ type Alert struct {
 	Reason    string  `json:"reason,omitempty"`
 	OpenedAt  int64   `json:"openedAt,omitempty"`
 	ClosedAt  int64   `json:"closedAt,omitempty"`
+	Memo      string  `json:"memo,omitempty"`
 }
 
 // AlertsResp includes alert and next id
@@ -50,6 +51,12 @@ type AlertsResp struct {
 	NextID string   `json:"nextId,omitempty"`
 }
 
+type UpdateAlertParan struct {
+	Memo string `json:"memo,omitempty"`
+}
+
+type UpdateAlertResponse = UpdateAlertParan
+
 func (c *Client) findAlertsWithParam(v url.Values) (*AlertsResp, error) {
 	var d AlertsResp
 	u := c.urlFor("/api/v0/alerts")
@@ -138,3 +145,20 @@ func (c *Client) CloseAlert(alertID string, reason string) (*Alert, error) {
 
 	return data, nil
 }
+
+// UpdateAlert updates a Alert
+func (c *Client) UpdateAlert(alertID string, param UpdateAlertParan) (*UpdateAlertResponse, error) {
+	resp, err := c.PutJSON(fmt.Sprintf("/api/v0/alerts/%s", alertID), param)
+	defer closeResponse(resp)
+	if err != nil {
+		return nil, err
+	}
+
+	var data = UpdateAlertResponse{}
+	err = json.NewDecoder(resp.Body).Decode(&data)
+	if err != nil {
+		return nil, err
+	}
+
+	return &data, nil
+}