Diffusion and sputtering techniques are described for applying low resistance, highly transparent, antireflecting, electrical contacts to CdS. The diffusion process entails heating CdS for several minutes in the presence of indium vapor. The resulting crystal surface resistance has been adjusted to range as low as 12 ohms/square without any observable crystal discoloration. The sputtering process employs an 82–18% indium‐tin alloy that is placed onto the crystal surface using oxygen as the sputtering atmosphere. The resulting film is Sn‐doped In2O3, measuring 100–150 ohms/square, and showing 80–100% transmittance from 4600 to 20 000 A.