Content profile fields on registration form by role I have two main users roles: authenticated and agent.

First role uses content profile fields on registration form.

Users with the agent role can only be created by admins but agent doesn't need content profile fields.

In user_add_form the content profile fields is added as well so the admin must fill them.

How can I disable those fields when an admin want to create user with the agent role?
You can use hook_form_alter to alter the form. This is how the profile fields is added and they can be removed this way as well.

You have to make sure that your custom module is run after the profile module, which may require that you alter the weight of the module. This is merely a value in the system table.