Background: Heterotopic ossification was known previously as myositis ossificans, and newly called ectopic bone, neurogenic ossifying fibromyopathy, or paraosteoarthropathy. All these names refer to new bone formation out of the skeleton in tissues. Methodology: The study was done in Ibn Al-Kuff rehabilitation hospital in Baghdad between April 1995 and January 1996. patients who were admitted to hospital with early spinal cord injured were included in the study. Results: Twenty five inpatients forming (group A), their injuries were between (C4?L1). Two patients developed heterotopic ossification in both hip joints and one of them developed heterotopic ossification in both knee joints, they were males, their level of injury were D9 and L1 consecutively. The time interval between spinal cord injured and heterotopic ossification formation was 4 months in one and 6 months in the other patient. The other 25 spinal cord injured patients with heterotopic ossification (group B) were examined clinically and their notes, reviewed. Their injuries were between (C5?L1). The early signs of heterotopic ossification formation, and levels of alkaline phosphatase as recorded in their notes, were similar to (group A) patients. Conclusion: It is concluded that chest injury fracture, bladder stones are possible risk factors for heterotopic formation.