Preheat oven to 350
Combine flour and baking soda in bowl. Set aside.
Cream together butter and sugar in a bowl. Beat in instant pudding mix until blended. Add vanilla and eggs. Blend.
Add flour mixture and combine thourougly. Add in chocolate chips and then gently fold in marshmallows.
Place rounded tablespoon sized dough on ungreased cookie sheet. Bake for 10-12 minutes. Let cool for 2 minutes before removing from cookie sheet.