A longitudinal community health study was commenced in a neighborhood of western Jerusalem in 1969. Its main aims were the investigation of etiologic factors in selected common diseases and disabilities, the development and testing of epidemiologic tools for use in community diagnosis, the provision of a factual basis for decisions concerning community health care for the population studied, and the use of the findings in an evaluation of the effectiveness of community health care. In the first round, 90% of residents 25 or more years old were interviewed and 81% were examined. Among children under 15 years of age, the corresponding rates were 94 and 83%. Response was low among persons in the age range 15 to 24 years, especially males. People who were concerned about their health were readier to be examined. Response was not related to region of birth, education or other variables. The possible bias introduced by nonresponse appeared to be small except in the age group 15 to 24 years.