Three groups of patients in treatment were assessed for impotence, using MMPI-derived Impotence Scale. Group I were 46 patients who had been screened and scheduled for a penile prosthesis when the impotence resulted from known organic causes (biogenic). Group II were 198 patients in a sexual dysfunction clinic, for whom biogenic causes had been ruled out (psychogenic). Group III were 51 substance abusers in drug rehabilitation. While scores on the Impotence Scale did not distinguish between the biogenic and psychogenic groups, the scores were almost three times higher than average scores among subjects in the standardization sample. MMPI-derived Impotence Scale scores were similarly elevated among the substance abusers. Results suggest that the Impotence Scale may serve as a useful screening tool to alert clinicians to the possibility of erectile dysfunction for which further clinical evaluation would be required.