Background: Paediatric inguinal hernias commonly result from congenital persistence of processus vaginalis (PV) and usually require surgical correction. This patent processus vaginalis can be bilateral and if one side is clinically unapparent during the surgery for the contralateral side, a metachronous hernia may result leading to a second operation and anaesthesia. Preoperative groin ultrasonography has been suggested as a tool to reduce the incidence of metachronous contralateral inguinal hernia. Objectives: This study aims to determine the diagnostic accuracy of ultrasonography in detecting clinically unapparent contralateral inguinal hernia in children. The study also aims to determine whether the exploration of the groin in paediatric inguinal hernia based on ultrasonography findings is justified. Patients and Methods: This is a fourteen-month prospective study of 42 patients that presented to the Paediatric Surgery Units of the University of Nigeria Teaching Hospital, Ituku/Ozalla, Enugu State, with clinically apparent unilateral inguinal, inguinoscrotal/inguinolabial hernias. All patients had an ultrasound of the contralateral inguinal region to detect unapparent inguinal hernia based on Toki’s classification using a high-resolution 7.5-11MHz linear transducer. Patients with positive ultrasonography findings had contralateral inguinal exploration. Ultrasound and intra-operative features were compared to determine the diagnostic accuracy of ultrasonography. A structured proforma was used to collect data and SPSS statistics version 25.0 was used to analyze the data. Test of significance was applied where appropriate using fisher’s exact test. The confidence interval was calculated at a 95% level and a p-value of 0.05 was considered to be statistically significant. Results: The mean age of the patients was 3 years (range of 1 month to 15 years) and the median Body Mass Index (BMI) was 14.3kg/m2(range of 11.1kg/m2 to 20.1kg/m2). A total of 7 patients (16.7%) had