I would also love to have this feature.
thanks
Florian

If you search for subtasks in the Ideas section you'll see we've been asking for this function for over 3 years now:

http://www.rememberthemilk.com/forums/ideas/180/

Some of us have even left RTM and moved to ToodleDo for this and perhaps other reasons.

This would be so great I'd like to keep a unified structure with my "Big 3" (Gmail, Evernote, RTM) and so far it's been a simple one (As suggested by Lifehacker):

Business/Clients
Business/Receipts
etc...

But using this method is starting to make RTM a big ol' mess!

Thanks to anyone at RTM that might hear our plea.

-Daniel

This was my first question after I signed up. I need to be able to list subtasks under my tasks. When will this be available? Looks like I am not the only one. Thanks for the suggestion of a better application.

Is RTM still working on development? Please inform us more about what and when new things can be expected.