Manual breast pumps are operated by squeezing or pulling a handle in a repetitive fashion, allowing the user to directly control the pressure and frequency of milk expression. This style is recommended for infrequent usage such as when a woman is away from her baby for a single feeding.

Electric breast pumps are powered by a motor which supplies suction through plastic tubing to a horn that fits over the nipple. The portions of the pump that come into direct contact with the expressed milk must be sterilized to prevent contamination. This style provides a lot more suction, making pumping significantly faster, and allows pumping of both breasts at the same time. Electric breast pumps are ideal for when a mother will be pumping daily. Electric breast pumps are larger than manual ones, but portable models are available (e.g. in a backpack or shoulder bag) that allow the mother to transport the pump. Some manufacturers have battery packs or built in batteries to allow portable operation of the pumps.