We examined in a cross-sectional study, 47 children (mean age 7.7 (1-16) years) with osteogenesis imperfecta (OI) to find the prevalence of spinal deformities and to correlate these observations with anthropometry. The associations between dentinogenesis imperfecta, joint hypermobility and spinal deformities were also studied. Disproportion in stature in OI type I and type IV was mainly caused by spinal involvement, as evidenced by a greater decrease in body height than in leg length. In OI type I, the decrease in sitting height was mainly caused by platyspondyly, whereas in OI types III and IV, it was also caused by progressive scoliosis and kyphosis. Scoliosis was present in 22 children, and pathological kyphosis in 18, mainly in the severe OI types. Basilar impression was observed in 10 children, mainly in type III. Children with dentinogenesis imperfecta seemed to be prone to develop scoliosis, pathological kyphosis and basilar impression. Children with generalized joint hypermobility were less prone to develop scoliosis and basilar impression. Our observations may contribute to a better understanding of the risk factors for progressive spinal deformities in OI.