Within a cohort of 340 police officers, six incident cases of testicular cancer occurred between 1979 and 1991 (O/E 6.9; p < 0.001, Poisson distribution). Occupational use of hand-held radar was the only shared risk factor among all six officers, and all routinely held the radar gun directly in close proximity to their testicles. Health effects of occupational radar use have not been widely studied, and further research into a possible association with testicular cancer is warranted.