diff --git a/backend/sftp/sftp.go b/backend/sftp/sftp.go
index 4b3c9dec5..6453a9783 100644
--- a/backend/sftp/sftp.go
+++ b/backend/sftp/sftp.go
@@ -5,6 +5,7 @@
 package sftp
 
 import (
+	"fmt"
 	"io"
 	"io/ioutil"
 	"os"
@@ -17,6 +18,7 @@ import (
 
 	"github.com/ncw/rclone/fs"
 	"github.com/ncw/rclone/fs/config"
+	"github.com/ncw/rclone/fs/config/flags"
 	"github.com/ncw/rclone/fs/config/obscure"
 	"github.com/ncw/rclone/fs/fshttp"
 	"github.com/ncw/rclone/fs/hash"
@@ -35,6 +37,9 @@ const (
 
 var (
 	currentUser = readCurrentUser()
+
+	// Flags
+	sftpAskPassword = flags.BoolP("sftp-ask-password", "", false, "Allow asking for SFTP password when needed.")
 )
 
 func init() {
@@ -331,6 +336,13 @@ func NewFs(name, root string) (fs.Fs, error) {
 		sshConfig.Auth = append(sshConfig.Auth, ssh.Password(clearpass))
 	}
 
+	// Ask for password if none was defined and we're allowed to
+	if pass == "" && *sftpAskPassword {
+		fmt.Fprint(os.Stderr, "Enter SFTP password: ")
+		clearpass := config.ReadPassword()
+		sshConfig.Auth = append(sshConfig.Auth, ssh.Password(clearpass))
+	}
+
 	f := &Fs{
 		name:              name,
 		root:              root,
diff --git a/docs/content/sftp.md b/docs/content/sftp.md
index 6dab5afb5..fa79f2ae2 100644
--- a/docs/content/sftp.md
+++ b/docs/content/sftp.md
@@ -127,6 +127,9 @@ instance `/home/$USER/.ssh/id_rsa`.
 If you don't specify `pass` or `key_file` then rclone will attempt to
 contact an ssh-agent.
 
+If you set the `--sftp-ask-password` option, rclone will prompt for a
+password when needed and no password has been configured.
+
 ### ssh-agent on macOS ###
 
 Note that there seem to be various problems with using an ssh-agent on
@@ -141,6 +144,14 @@ And then at the end of the session
 
 These commands can be used in scripts of course.
 
+### Specific options ###
+
+Here are the command line options specific to this remote.
+
+#### --sftp-ask-password ####
+
+Ask for the SFTP password if needed when no password has been configured.
+
 ### Modified time ###
 
 Modified times are stored on the server to 1 second precision.