Behavioral and emotional problems experienced in early childhood may have a major impact on the development and functioning of a child, leading to a number of psychiatric problems at a later age. The purpose of this study was to determine the incidence of psychiatric disorders in 3-5-year-old children presenting to the Outpatients Department and in the general population, and the relationship between psychiatric disorders and the sociodemographic characteristics of the children. This was a cross-sectional study carried out in Kocaeli, Turkey. Data were collected from two different groups, one representing the general population and the other based on children presenting to the Pediatric Psychiatry Outpatients Department at Kocaeli University Faculty of Medicine. Of the 309 children in the study, 187 (60.5%) were boys and 122 (39.5%) were girls. Children aged 3-5 years (n = 81) were assessed by clinical examination. The mean age of the children was 3.94 +/- 0.81 years. No significant difference was observed between the groups in terms of parents' age groups, presence of consanguineous marriage, family structure, and siblings. The mothers were assessed in terms of regular visits to their physicians, major medical conditions, medication use, alcohol or tobacco consumption, and stress factors during their pregnancies. No significant difference was found between the study samples. The presence of a medical problem after birth was significantly more common in the clinical sample. Of the children in the clinical sample, 79% had at least one psychiatric problem, while the ratio for the general population sample was 41.7%.