In children, fractures following minimal trauma is the most prevalent sign and a hallmark of osteogenesis imperfecta (OI). Long bones, particularly in the lower limbs, are frequent fracture sites in children with OI. The diagnosis is based mainly on history, physical findings and radiographic features. In this report familial clustering, the clinical and epidemiological characteristics of two female siblings (including their mother) with OI are described while the newer classification, the differential diagnosis and the aims of therapy are also emphasized.