The present invention provides in one aspect for a bracket for use with insulated forms for concrete walls. The bracket has an attachment plate for overlying the exterior of the insulated form to provide for a means of attaching the header or rim joist to the bracket. The bracket is provided an anchoring plate extending from the attaching plate for insertion into the interior of the insulated form. The present invention also provides for a method of attaching a header or rim joist to a concrete wall formed using insulated forms. The method involves cutting a vertical slot in the insulated form and inserting a bracket into the slot. The bracket has an attachment plate for overlying the exterior surface of the insulated form and an anchoring plate extending from the attachment plate through the slot into the interior of the insulated form. Concrete is poured into the form and allowed to set, after which the header or rim joist is attached to the brackets.