Introduction. To date, the problem of the presence of post voiding residual (PVR) in children remains urgent. PVR is the amount of urine remaining in the bladder after its voluntary emptying. The following conditions are associated with this, requiring the participation of a specialist: urinary tract infection, urolithiasis, bladder dysfunction.

Materials and methods. A group of 125 children who were treated at medical centre «Alenka» for bladder dysfunction was under observation. In 42 of them, PVR was detected during uroflowmetric monitoring (UM) for 2 days on the SIGMA model uroflowmeter device, option F.

Results. Processing and analysis of the data obtained allowed us to conclude that the reliability of the ultrasound diagnostic method is low (x2 =0.013; p>0.05) when detecting PVR and high during voiding cystourethrography (x2= 3.889; p<0.05). During uroflowmetric monitoring, there was a tendency to decrease the frequency of PVR with age. The average effective volume was reduced in 34 children (20 boys and 14 girls), was within the age norm in 3 boys and increased in 5 children (3 boys and 2 girls). Thus, PVR occurred almost 7 times more often with a decrease in the volume of the bladder than with an increase in it, which changes the idea of the nature of residual urine.

Conclusion. According to the conducted research, it becomes clear that the symptom of residual urine is a common sign in pediatric urological practice. The most accurate method for determining PVR is two-day uroflowmonitoring, followed by miction cystography in terms of accuracy. Ultrasound examination reveals residual urine unreliably.