Diabetes mellitus (DM) can be accepted as a heterogenous multi organ disorder that can affect various systems of the human body. Disorders include retinopathy, neuropathy, cardiomyopathy, musculoskeletal abnormalities such as diminished bone formation and bone healing retardation. Low bone mineral density is often mentioned as a complication for patients with insulin dependent diabetes mellitus (type I DM). Streptozotocin (STZ) induced diabetic rats are good models for investigation of the complications of insulin dependent diabetes. In the present study, the effects of STZ induced diabetes on the mineral environment of rat bones namely femur and tibia were studied by Fourier transform infrared (FTIR) spectroscopic technique. The results revealed that mineral crystal sizes increased and carbonate content decreased for diabetic femur and tibia. These changes can be due to the formation of osteoporosis which is widely seen in diabetic patients.