We report on 2 male patients treated with zidovudine (azidothymidine), who developed longitudinally striated coloration of their nails and lentigines. Both patients are suffering from advanced HIV disease with opportunistic infections. Following treatment with zidovudine 1200 mg daily for 3 and 6 months resp., we observed longitudinal streaks of brownish color in both patients; they did not receive any other drugs known to induce discoloration of the nail plate. Our cases possibly reflect antiproliferative effects of zidovudine at the particularly susceptible nail matrix.