Using a comma before the word "and" depends on the thought and construction of your sentence. A comma is usually used when merging two independent clauses. 1. The car was taken by my sister, and was later found near her boyfriend's house. [The car was taken by my sister.] + [The car was later found near her boyfriend's house.] 2. Carla started dancing ballet when she was 5 years old, and is now teaching ballet to kids. [Carla started dancing ballet when she was 5 years old.] + [Carla is now teaching ballet to kids.] If the independent clauses are short, there's no need to use a comma -- but it can still be used. eg. I drank scotch, and Shelley had water. I drank scotch and Shelley had water. When enumerating, a comma isn't supposed to be used before "and." eg. 1. I would like a slice of bread with butter, strawberry jam, bacon on the side and orange juice. 2. Exercising helps you stay fit and healthy.