Despite the well-established health hazards associated with cigarette smoking, research indicates that many smokers underestimate their personal susceptibility to these health risks. Previous studies have examined this discrepancy, but validation of measures is lacking. The purpose of this investigation was to develop and validate a measure of smokers' perceptions of their own smoking-related health consequences. The Smokers' Perceived Health Risk Evaluation (SPHERE) was administered at baseline to 255 smokers recruited for a cessation trial at two methadone maintenance treatment programs in Providence, Rhode Island. The scale consisted of two 3-item subscales each demonstrating good to excellent internal consistency reliability: Smoking-Related Health (alpha = .66) and Smoking-Related Risk (alpha = .87). The subscales correlated with common smoking-related pulmonary symptoms, previous treatment for smoking-related illnesses, the physical health functioning scale of the SF-12, and participants' perceived importance of a cessation intervention. The SPHERE is a reliable instrument that captures unique dimensions of smokers' health expectancy.