Few measures are available to assess the health status of the growing numbers of children who now survive long-term with chronic physical disorders. A Functional Status Measure, FS I, that had considerable promise for measuring individual child health status and characterizing populations was developed in 1978. This paper describes a revised version of that measures. Data were collected using a new sample of 732 children (aged 0 to 16 years) with and without chronic physical conditions in order to assess the psychometric properties of the new instrument. The FS II(R) has both a long (43-item) and a short (14-item) version. The long version has a total score derived from a one factor solution and a two factor solution consisting of General Health and Stage Specific factors for each age group. The 14-item version of FS II(R) uses a common core of items across the entire age span. Internal consistency estimates (alphas) for the factor-based and 14-item versions are all greater than 0.80. At each age, long and short versions behave similarly in a wide range of tests of discriminant, construct, and content validity--strong support that they constitute a common measure. The FS II(R) has excellent psychometric properties and provides concise measures of health status of children spanning the entire childhood age range from 0 to 16 years. It has particular strengths for the measurement of health status of children with chronic physical conditions who are not disabled.