Objective: The aims were to quantify and evaluate the radiation doses and to estimate the radiation risk for the paediatric patients undergoing VCUG according to the protocol used in Siriraj Hospital. Methods: Among 93 children of the age of 0-15 years who underwent VCUG at Siriraj Hospital, we reported the patient’s data, the radiation doses determined by a DAP meter and the baseline data including the entrance skin dose (ESD), dose area product (DAP) and the effective dose according to the patient’s age. Results: The mean ESD, DAP and effective doses of 93 paediatric patients were 3.63 mGy, 92.9 cGycm2 and 0.20 mSv, respectively. The initial local DRLs of DAP for VCUG examination at Siriraj Hospital were 37, 77 and 105 cGy.cm2 in the age range of 0-1, >1-5, and >5-10 years, respectively. The ESD, DAP and effective doses were in ranges of 0.36-81.96 mGy, 1.37-1506.90 cGy.cm2 and 0.003-3.16 mSv, respectively. Conclusion: The initial local DRLs of DAP for VCUG examinations at Siriraj Hospital were less than in NRPB and Siriwiladluk T, et al in the age range of 0-1, >1-5, and >5-10 years. Due to the small number of patients at the age of >10-15 years (n=4), it was inconclusive of the dose level in this age group. The lifetime risk of radiation induced cancer was approximately calculated to be 2.6 per 100,000.