If you have Tumblr account Yahoo, you can delete it by following these steps:

  1. Log in to your Tumblr account.
  2. Click the “delete account” button at the top of the page.
  3. Type in the email address of your Tumblr user name and password and click the “delete” button.
  4. YourTumblr account will be deleted and all of your posts will be lost.