diff --git a/cmd/cmd.go b/cmd/cmd.go
index d34e5e3f6..6ccd1c355 100644
--- a/cmd/cmd.go
+++ b/cmd/cmd.go
@@ -8,6 +8,7 @@ func CreateCommands() []*cli.Command {
 		createRun(),
 		createRevoke(),
 		createRenew(),
+		createRegister(),
 		createDNSHelp(),
 		createList(),
 	}
diff --git a/cmd/cmd_register.go b/cmd/cmd_register.go
index 395c5bbb5..8e64fe4a7 100644
--- a/cmd/cmd_register.go
+++ b/cmd/cmd_register.go
@@ -8,14 +8,13 @@ import (
 	"os"
 	"strings"
 
+	"github.com/go-acme/lego/v5/cmd/internal/storage"
 	"github.com/go-acme/lego/v5/lego"
 	"github.com/go-acme/lego/v5/log"
 	"github.com/go-acme/lego/v5/registration"
 	"github.com/urfave/cli/v3"
 )
 
-// TODO(ldez): add register command.
-
 const rootPathWarningMessage = `!!!! HEADS UP !!!!
 
 Your account credentials have been saved in your
@@ -27,6 +26,55 @@ generated by lego and certificates obtained from the ACME
 server. Making regular backups of this folder is ideal.
 `
 
+func createRegister() *cli.Command {
+	return &cli.Command{
+		Name:   "register",
+		Usage:  "Register an account.",
+		Action: register,
+		Flags:  createRegisterFlags(),
+	}
+}
+
+func register(ctx context.Context, cmd *cli.Command) error {
+	keyType, err := getKeyType(cmd.String(flgKeyType))
+	if err != nil {
+		return fmt.Errorf("get the key type: %w", err)
+	}
+
+	accountsStorage, err := storage.NewAccountsStorage(newAccountsStorageConfig(cmd))
+	if err != nil {
+		return fmt.Errorf("accounts storage initialization: %w", err)
+	}
+
+	account, err := accountsStorage.Get(ctx, keyType)
+	if err != nil {
+		return fmt.Errorf("set up account: %w", err)
+	}
+
+	if account.Registration == nil {
+		client, err := newClient(cmd, account, keyType)
+		if err != nil {
+			return fmt.Errorf("new client: %w", err)
+		}
+
+		reg, err := registerAccount(ctx, cmd, client)
+		if err != nil {
+			return fmt.Errorf("could not complete registration: %w", err)
+		}
+
+		account.Registration = reg
+		if err = accountsStorage.Save(account); err != nil {
+			return fmt.Errorf("could not save the account file: %w", err)
+		}
+
+		fmt.Printf(rootPathWarningMessage, accountsStorage.GetRootPath())
+	} else {
+		log.Info("Account already registered, skipping.")
+	}
+
+	return nil
+}
+
 func registerAccount(ctx context.Context, cmd *cli.Command, client *lego.Client) (*registration.Resource, error) {
 	accepted := handleTOS(cmd, client)
 	if !accepted {
diff --git a/cmd/flags.go b/cmd/flags.go
index 13a081d36..b8fa75ce4 100644
--- a/cmd/flags.go
+++ b/cmd/flags.go
@@ -512,6 +512,17 @@ func createListFlags() []cli.Flag {
 	}
 }
 
+func createRegisterFlags() []cli.Flag {
+	flags := []cli.Flag{
+		CreatePathFlag(true),
+	}
+
+	flags = append(flags, CreateACMEClientFlags()...)
+	flags = append(flags, CreateAccountFlags()...)
+
+	return flags
+}
+
 func CreateDomainFlag() cli.Flag {
 	return &cli.StringSliceFlag{
 		Name:    flgDomains,
diff --git a/docs/data/zz_cli_help.toml b/docs/data/zz_cli_help.toml
index 629b05d6a..892651bbe 100644
--- a/docs/data/zz_cli_help.toml
+++ b/docs/data/zz_cli_help.toml
@@ -11,12 +11,13 @@ USAGE:
    lego [global options] [command [command options]]
 
 COMMANDS:
-   run      Register an account, then create and install a certificate
-   revoke   Revoke a certificate
-   renew    Renew a certificate
-   dnshelp  Shows additional help for the '--dns' global option
-   list     Display certificates and accounts information.
-   help, h  Shows a list of commands or help for one command
+   run       Register an account, then create and install a certificate
+   revoke    Revoke a certificate
+   renew     Renew a certificate
+   register  Register an account.
+   dnshelp   Shows additional help for the '--dns' global option
+   list      Display certificates and accounts information.
+   help, h   Shows a list of commands or help for one command
 
 GLOBAL OPTIONS:
    --help, -h  show help