diff --git a/api/queries_issue.go b/api/queries_issue.go
index d607901a3..3cfd853bd 100644
--- a/api/queries_issue.go
+++ b/api/queries_issue.go
@@ -251,8 +251,8 @@ func IssueList(client *Client, repo ghrepo.Interface, state string, labels []str
 
 	if milestoneString != "" {
 		var milestone *RepoMilestone
-		if milestoneNumber, err := strconv.Atoi(milestoneString); err == nil {
-			milestone, err = MilestoneByNumber(client, repo, milestoneNumber)
+		if milestoneNumber, err := strconv.ParseInt(milestoneString, 10, 32); err == nil {
+			milestone, err = MilestoneByNumber(client, repo, int32(milestoneNumber))
 			if err != nil {
 				return nil, err
 			}
diff --git a/api/queries_repo.go b/api/queries_repo.go
index fdbd13e92..9fd8b05bb 100644
--- a/api/queries_repo.go
+++ b/api/queries_repo.go
@@ -840,7 +840,7 @@ func MilestoneByTitle(client *Client, repo ghrepo.Interface, title string) (*Rep
 	return nil, fmt.Errorf("no milestone found with title %q", title)
 }
 
-func MilestoneByNumber(client *Client, repo ghrepo.Interface, number int) (*RepoMilestone, error) {
+func MilestoneByNumber(client *Client, repo ghrepo.Interface, number int32) (*RepoMilestone, error) {
 	var query struct {
 		Repository struct {
 			Milestone *RepoMilestone `graphql:"milestone(number: $number)"`