The Sickness Impact Profile (SIP), a measure of health status, is being developed as an outcome measure of health care. A preliminary study of the validity of the SIP was conducted on a sample of 278 subjects who were grouped into four subsamples differing in kind and severity of sickness. Selfassessment of health status, clinician assessment of health status, and other measures of dysfunction were used as criteria. SIP scores discriminated among subsamples, and correlations between criterion measures and SIP scores provided evidence for the validity of the SIP. Differences among the correlations obtained for each criterion measure with SIP score are discussed in terms of the need for the development of criterion measures that can be expected to differentially relate to the constructs inherent in the SIP.