Introduction: Osteogenesis imperfecta (OI) is a hereditary disease that impairs the quality of life by frequent bone fractures. The objective of our study is to retrospectively evaluate patients diagnosed with OI and to come up with helpful data that will assist developing new diagnosis and treatment protocols. Materials and Methods: Twenty-eight cases with OI who were followed-up in our clinic were retrospectively evaluated. Clinical classification of OI was done. Age, sex, and oxologic data were evaluated. Height, weight and body mass index (BMI) data was given as standard deviation score (SDS). Family history of fracture and consanguineous marriage was sought. Blue sclera and presence of deformity was evaluated on physical examination. Results: Out of the 28 cases in our study, 14 (50%) were boys, 14 (50%) were girls, and mean age was 7.48±5.09 years. Mean age of diagnosis was 25.59±39.59 months. Ten cases (47.6%) had OI, and 7 cases (25%) had consanguineous marriage in their family history. The cases were separated into autosomal dominant 4 clinical types according to Sillence classification as follows; 13 cases (46.4%) type 1, 10 cases (35.7%) type 3, and 5 cases (17.9%) type 4. The mean average basal dual energy X-ray absorptiometry Z score, mean height SDS, mean weight SDS and BMI SDS significantly increased for the cases after treatment (p<0.001). Conclusions: Treatment of OI with pamidronate was observed to increase bone mineral density, decrease number of fractures and pain, and improve the patient’s quality of life with inreasing mobility. Pamidronate is one of the most effective treatments of OI until a more effective treatment is found. On the other hand, since the long-term side effect of pamidronate on bones is not well-known, we think that randomised controlled studies still need to be done to determine the optimal time, interval and dose for bisphosphonate use.