The authors share herein their experience in diagnosis and treatment of deep vein thrombosis in neonates and nurselings. We examined a total of 132 infants undergoing treatment in an intensive care unit. Of these, 15 infants were diagnosed with various-localization thromboses. Ultrasonographic study was the main method of diagnosis. Management consisted in anticoagulant therapy. Timely administration of anticoagulant therapy made it possible to achieve complete recanalization of venous lumens in 80% of cases. Only 20% of infants were found to have vein occlusion preserved, thus requiring further follow up and treatment. Neither complications nor relapsing thromboses were observed. A conclusion was drawn that characteristic of neonates and infants under 12 months of life is a specific profile of etiopathogenesis of deep vein thrombosis. In the majority of cases thrombosis appears to be catheter-related, and only in sporadic cases it forms spontaneously. Treatment of thromboses is typically associated with high successfulness of medicamentous therapy