The isolation of a single pulse from a transversely excited atmospheric (TEA) CO2 laser, actively mode-locked by an acoustic loss modulator, is described. The single pulse selection has been achieved with the aid of a GaAs electrooptic shutter located either inside or outside the laser resonator. Pulses of 1 MW peak power and 2 ns duration have been recorded with instrument-limited precision. The availability of such pulses uncovers new possibilities for the investigation of laser–matter interactions at 10.6 μm.