In this study we have researched if there is an increased risk of developing a hematologic malignancy in carriers of constitutional chromosomal aberrations or they are just a random finding. We analysed karyotypes of bone marrow and peripheral blood in 1619 patients with hematologic malignancies and there were include 125 children and 1494 adult persons. In 22 patients or 1.36% we found constitutional chromosomal aberrations, which are around 1.6 - 2 times more of the frequency than in general, population (0.65 - 0.84%). They include 8 patients with the trisomy of chromosome 21, 9 patients with the aberrations of sex chromosomes and 5 patients with balanced structural aberrations. Among the carriers of the constitutional chromosomal aberrations, the trisomy of chromosome 21 was found in 0.49% of the patients, exclusively among children with the hematologic malignancies, which is about 3 times more than the frequency of the trisomy 21 found in general population, (0.12 - 0.17%) which is statistically relevant (p=0,051). The carriers of the other constitutional chromosomal aberrations were found in 0.87% patients with the hematologic malignancies and exclusively among the adult population, have not shown significant differences regarding general population (0.65 - 0.84%). In this research for the first time we have shown the data for our population which have confirmed numerous of studies that the only risk factor for the development of hematologic malignancies represents the trisomy of chromosome 21, while the other constitutional chromosomal aberrations are probably a random finding.