Two UV-inducible proteins have been detected in the yeast, Saccharomyces cerevisiae. The proteins have molecular weights of 78,000 Daltons and 23,000 Daltons. This induction is specific for UV-irradiation as exposure to X-rays, mitomycin C and heat shock does not result in the synthesis of the proteins. The larger (78 kD) protein is induced in various rad strains and in a rho degree cir degree strain. Attempts are being made to isolate the genes coding for these inducible proteins.