There is a paucity of Russian medical literature reporting lumbosacral transitional vertebrae in children and adolescents. Many important aspects of the condition including two nosologies of sacralization of the L5 vertebrae and lumbalization of the S1 vertebrae have been under-explored. The objective was to establish overall frequency and frequency of certain types of lumbosacral transitional vertebrae in children and adolescents who sustained a lumbar injury and to investigate clinical manifestations of the pathology. Material and methods A comprehensive examination of 312children aged 7 to 18 years who suffered a lumbar injury was performed. Lumbosacral transitional vertebrae was radiologically diagnosed in 19 (6.09 %) subjects. Grading system of A.E. Castellvi et al. (1984) was used to classify the pathology. Results From 19 patients with lumbosacral transitional vertebrae, sacralization of the L5 vertebrae was detected in 16 (84.21 %) individuals. Lumbalization of the S1 vertebrae was diagnosed in 3 (15.79 %) children. Type II (n = 13) and subtype "b" (n = 10) were most common. No types III and IV of the disease were seen. No clinical symptoms indicating the likelihood of having lumbosacral transitional vertebrae were observed in the patients prior to the lumbar injury. Conclusion The frequency of occurrence of lumbosacral transitional vertebrae and its structure were reviewed in children and adolescents. The patients demonstrated no clinical manifestations of the condition before the children sustained lumbar injuries. Various aspects of transitional lumbar vertebrae in children and adolescents require further study.