Seasonal affective disorder is considered as a clinical subtype of major depression. The criteria for seasonal pattern has been recently described in the international classification of mental disorders. The aim of this study was to compare the clinical characteristics of patients with major depression and with a seasonal and a non seasonal pattern. The study was conducted at the psychiatric ward at Monastir university hospital. 16 inpatients with major depression and seasonal pattern, diagnosed with DSM-IV criteria, were matched in age, sex and diagnostic sub-type to 32 inpatients with non seasonal mood disorders. Clinical symptoms and short term course during the most recent depressive episode were obtained. The onset of the depression with seasonal pattern was frequently in winter. It was marked by significantly higher rates of anxiety. The patients with seasonal depression had significantly higher rates of dysphoria, atypical vegetative symptomatology and lower rates of psychotic characteristics and suicidal thoughts. No differences were found as to the psychiatric family histories or the age at the first depressive episode. This study could focus of the novel psychiatric entity and may lead to the development of the genetic and neurobiologic research related to seasonal affective disorder