Beat the butter and sugar together in a large mixing bowl until creamy. Add the eggs one at time, then add the vanilla.In a separate bowl, mix the flour, cocoa, salt, and baking soda together. Add the dry ingredients into the wet ingredients and mix well. Stir in the chocolate chips.
Drop by teaspoonfuls onto ungreased baking sheets. Bake for 8-9 minutes. Do not overbake--cookies will be soft! Cool slightly on the baking sheet for removing to to racks to cool completely.