Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9x13 inch baking pan.
In a large bowl, cream together the butter and sugar until smooth. Beat in the molasses.
In a separate bowl, sift together the baking soda, ginger, cinnamon, and flour. Gradually stir the dry ingredients into the butter mixture. Beat in the eggs one at a time, mixing well after each addition.
Pour batter into prepared pan. Bake for 25 to 30 minutes in preheated oven.