A general consideration is presented for obtaining high repetition rates in passively mode-locked lasers with a nonlinear external coupled cavity. Without modification of the main cavity, as much as a sixfold increase over the original repetition rate of 76 MHz has been obtained in a coupled-cavity passively mode-locked Nd:YLF laser. At a constant average output power, the pulse width increases linearly, while the detuning range decreases with increasing repetition rates.