The process for developing and evaluating a comprehensive, self-report measure of quality of life in epilepsy (QOLIE) is described, and interim results for 64 patients are reported. A test battery of 98 quality-of-life items was constructed with use of the RAND 36-Item Health Survey as a generic core and adding other quality-of-life items, the latter derived from a literature review and expert opinion on areas of importance to people with mild to moderate epilepsy. Seventeen scales tapping unique quality-of-life dimensions were identified from this QOLIE test battery. The battery was administered to 64 adults with mild to moderate epilepsy and their proxies (relative or close friend) on two separate visits 2-3 weeks apart. Patients also completed a neuropsychological test battery on the first visit. Interim analysis of these data demonstrated that 16 of 17 scales on the QOLIE test battery are sufficiently reliable for group comparison: Cronbach's alpha for the 16 scales ranged from 0.73 to 0.88; test-retest reliability ranged from 0.56 to 0.88. Preliminary evaluation of validity confirmed hypothesized correlations between selected QOLIE scales and Profile of Mood State scales. Correlations between patient and proxy scores ranged from 0.29 to 0.69 (all statistically significant at p < 0.005). A more detailed, final analysis of data for over 300 patients currently enrolled in the study will be published later.