Stir together flour,cocoa,baking soda and salt. Beat butter and sugar in large bowl with mixer until fluffy. Add egs and vanilla;beat well. Gradually add flour,beating well.Stir in peanut butter chips.
Drop by rounded teaspoons onto ungreasted cookie sheet.Bake 8 to 9 minutes at 350 degrees. (do not over-bake cookies will be soft.They will puff and flatten while cooling)