Developmental diseases are one of the main reasons of pain and lameness in young dogs. Diseases that develops spontaneously and their etiology is unlighted are usually include pair of joints and or bones. This diseases cause structural changes in the extremities and uncomfortable experience of living for animals. The treatment to these diseases can be medical or surgical. Most of the affected dogs are fast growing and large breed. The pathologies that likely to be seen are craniomandibular osteopathy, hypertrophic osteodystrophy/ hypertrophic ostheopathy, Legg-Calve Perthés (avascular necrosis of the femoral head/ aseptic necrosis), panosteoitis, ostheochondrosis/ ostheochondrosis dissecans, elbow displasia (medial coronoid disease, ununited anconeal process, joint incompatibility), carpal laxity syndrome, delayed endochondral ossification. Basically; Radiography and CT, MRI or scintigraphy (scanning of the bones) can be used for diagnosis of developmental orthopedic diseases. Etiology, pathophysiology and progressions needs to be well understood for proper medical or surgical treatment of this developmental orthopedic diseases.