Hybrid systems composed of fuel cells and batteries combine the high energy density of fuel cells with the high power density of batteries. A dc/dc power converter is placed between the fuel cell and the battery to balance the power flow between them and greatly increase the peak output power of the hybrid. This paper presents an adaptive control strategy for active power sharing in the hybrid power source. This control strategy can adjust the output current setpoint of the fuel cell according to the state-of-charge (or voltage) of the battery, and is applicable in two topologies of active fuel cell/battery hybrids. The control strategy is implemented in Simulink and then tested under arbitrary load conditions through simulation and experiments. Simulation and experimental results show that the adaptive control strategy is able to adjust the fuel cell output current to adapt to the charge state of the battery, and appropriately distribute the electrical power between the fuel cell and the battery. Experiments demonstrate the generality of the adaptive control strategy.