Triploidy, the presence of an additional haploid set of chromosomes, is the cause of 20% of spontaneous abortions, premature births and perinatal deaths. The most common clinical signs of triploidy are: severe intrauterine growth retardation, macrocephaly, total syndactyly of third and fourth fingers and CNS, heart and renal defects. Hydatidiform mole, one of the characteristic features of pure triploidy, is found in more than 90% of cases. The survival of individuals with diploid/triploid mixoploidy is usually longer than of those with pure triploidy. The detailed clinical characteristics of two of our patients with triploidy diagnosed shortly after birth are presented. In one of them mixoploidy (lymphocytes/fibroblasts) was confirmed. In the second pure triploidy was identified in cultured lymphocytes. We discuss the clinical features in our patients and compare them with data from medical literature.