diff --git a/cmd/mailfull/command/domainlist.go b/cmd/mailfull/command/domainlist.go
new file mode 100644
index 0000000..11657d2
--- /dev/null
+++ b/cmd/mailfull/command/domainlist.go
@@ -0,0 +1,55 @@
+package command
+
+import (
+	"fmt"
+	"sort"
+
+	"github.com/directorz/mailfull-go"
+)
+
+// DomainListCommand represents a DomainListCommand.
+type DomainListCommand struct {
+	Meta
+}
+
+// Synopsis returns a one-line synopsis.
+func (c *DomainListCommand) Synopsis() string {
+	return "Show all domains."
+}
+
+// Help returns long-form help text.
+func (c *DomainListCommand) Help() string {
+	txt := fmt.Sprintf(`
+Usage:
+    %s %s
+
+Description:
+    Show all domains.
+`,
+		c.CmdName, c.SubCmdName)
+
+	return txt[1:]
+}
+
+// Run runs the command and returns the exit status.
+func (c *DomainListCommand) Run(args []string) int {
+	repo, err := mailfull.OpenRepository(".")
+	if err != nil {
+		fmt.Fprintf(c.UI.ErrorWriter, "[ERR] %v\n", err)
+		return 1
+	}
+
+	domains, err := repo.Domains()
+	if err != nil {
+		fmt.Fprintf(c.UI.ErrorWriter, "[ERR] %v\n", err)
+		return 1
+	}
+
+	sort.Sort(mailfull.DomainSlice(domains))
+
+	for _, domain := range domains {
+		fmt.Fprintf(c.UI.Writer, "%s\n", domain.Name())
+	}
+
+	return 0
+}
diff --git a/cmd/mailfull/main.go b/cmd/mailfull/main.go
index 7c7001f..8bff108 100644
--- a/cmd/mailfull/main.go
+++ b/cmd/mailfull/main.go
@@ -43,6 +43,10 @@ func main() {
 			meta.SubCmdName = c.Subcommand()
 			return &command.InitCommand{Meta: meta}, nil
 		},
+		"domainlist": func() (cli.Command, error) {
+			meta.SubCmdName = c.Subcommand()
+			return &command.DomainListCommand{Meta: meta}, nil
+		},
 	}
 
 	exitCode, err := c.Run()