To the Editor: Links between suicide, seasonal affective disorder, and latitude are known. We present new and potentially useful information linking seasonal light variation to suicide. To our knowledge, there have been no previous reports of the association between latitude and suicide rates in the extreme southern hemisphere. We found no studies in MEDLINE that included countries south of 45° south latitude. Argentina is the only country with an appreciable population below 45° south latitude. We analyzed suicide rates in the three southernmost provinces of Argentina (Chubut, Santa Cruz, and Tierra del Fuego); suicide rates were 5.9 (in women) and 21.4 (in men) per 100,000 compared to national rates of 3.1 (in women) and 15.5 (in men) (1). Native American population distribution in Argentina shows that the northernmost province, Salta, had the highest percent of Native Americans (15%), far higher than the national average of about 0.5% (Instituto Nacional de Asuntos Indigenas, Buenos Aires). This information should encourage researchers studying the effect of seasonal or diurnal light variation on suicide rates.