Aim. The aim of the study was to compare working memory and executive function capacity in the first years of illness, in early-onset schizophrenic subjects with later-onset patients, who became ill in adulthood. The aim was also to asses the possible level of cognitive dysfunction in two groups of schizophrenic patients in partial remission of psychopathological symptoms. Method. 25 adolescent schizophrenic patients, aged 15-18 (Mean 17) years during partial remission of symptoms (PANSS-77) and 25 adult schizophrenic patients, aged 20-37 (Mean 26.9) years during partial remission of symptoms (PANSS Mean 56). The control group consisted of 25 healthy adolescents, aged 15-18 (Mean 17) years and 25 healthy adults, aged 21-39 (Mean 26.8) years. Results and conclusions. In schizophrenic patients with various types of illness onset (early vs. later), the significant dysfunction of working memory and executive function, compared to healthy controls were found. In the first years of the disease there were no differences in the level of working memory and executive functions impairment in patients with early-onset compared with patients with illness onset in adulthood.