We investigate frequency-modulation mode locking of a diode-laser-pumped Nd:YAG laser. Pulses of 12-psec duration up to a repetition rate of 350 MHz have been obtained with no intracavity elements other than a lithium niobate phase modulator. These pulses are approximately twice transform limited and to our knowledge are the shortest pulses that have been produced by an actively mode-locked Nd:YAG laser. When the laser was pumped by a 500-mW laser-diode array the average lasing power at 1.064 microm was 65 mW, which corresponds to a peak power of 15 W.