The persistence of several types of viruses on hard, inanimate surfaces under different relative humidities, temperatures, and types of surfaces was investigated. No differences in survival on glass, vinyl asbestos tile, ceramic tile, and stainless steel were found. Under conditions of low humidity and room temperature, adenovirus, poliovirus, and herpes simplex virus survived for at least 8 weeks. Vaccinia and coxsackie viruses survived for at least 2 weeks but differences due to humidity and temperature were not detected. The long-term survival of viruses on common surfaces found in many environments, in addition to the laboratory, emphasizes the possible role of hard surfaces in the transmission of viruses.