A method of charging a battery pack that can prevent a battery or an external power source from being damaged due to a trickle charge current in order to improve battery safety, and the battery itself. The method of charging the battery pack includes determining whether a charge current exists, determining whether the charge current and a charge voltage are changed if determined that the charge current exists, determining whether the charge current is changed from a first current level to a second current level less than the first current level, and a present voltage level of the battery is less than a former voltage level if determined that the charge current and the charge voltage are changed, and maintaining the charge current at the second current level for a predetermined maintenance time if determined that the present voltage level of the battery is less than the former voltage level.