A cooking apparatus and method thereof capable of performing a cooking process based upon a cooking condition corresponding to the amount of food introduced into a cooking chamber when the cooking process is performed using a bar code printed on a food package to be cooked. The cooking method includes reading a bar code storing a reference weight of food to be cooked and a cooking condition based on the reference weight, sensing the weight of food introduced into a cooking chamber, calculating a number of servings of the food introduced into the cooking chamber by using the weight of the food introduced into the cooking chamber and the reference weight of the food, and changing the cooking condition to correspond to the number of servings of the food introduced into the cooking chamber, when the number of servings of the food introduced into the cooking chamber varies from a number of servings corresponding to the reference weight of the food, to thereby set a final cooking condition is corresponding to the changed cooking condition.