This letter gives an early assessment of deep submicron planar bulk CMOS devices for millimeter wave power amplifier (PA) applications. Using load pull measurements, a record high power density of 100 mW/mm and a transducer gain of 7 dB at 35 GHz were achieved for a 40 nm physical gate length CMOS device with a total gate width of 192 μm. Furthermore a peak PAE of 33% was reached. This shows that 40 nm gate length CMOS is feasible for medium PAs in the millimeter wave region.