OBJECTIVE The goals of this study are to provide estimates of the prevalence of seasonal affective disorder in Alaska, to examine sociodemographic correlates, and to evaluate the relation between seasonal affective disorder and general depression. METHODS A random sample of 283 residents of Fairbanks who had lived in Alaska for 3 years or more were interviewed with the Seasonal Pattern Assessment Questionnaire and the Center for Epidemiologic Studies Depression Scale (CES-D Scale). RESULTS Twenty-six (9.2%) of the subjects met diagnostic criteria for seasonal affective disorder, one of the highest figures yet reported. These cyclic winter affective disorders occurred more often in women than men (ratio = 3:2) and were less prevalent among residents who were older than 40 years of age. Assessment of depression with the CES-D Scale supported the diagnostic classification of respondents and the differentiation of seasonal affective disorder from other depression. CONCLUSIONS This study supports the conclusions that seasonal affective disorder is prevalent in northern populations and that sex and age may represent the major risk factors that differentiate it from the general experience of depression in northern communities.