We mailed a questionnaire to patients affected with seasonal affective disorder (SAD) to determine patterns of self-selected light use and efficacy of treatment. Data obtained from 127 patients who responded indicate that despite, inconvenience and other use-limiting factors, many patients with SAD derive sustained benefit from phototherapy over months. No consistent pattern or duration of effective treatment emerged. Development of a less cumbersome means of delivering phototherapy and reimbursement by insurance companies remain concerns to patients.