Computed Tomography(CT) of the hip was done on 37 patients those who have been suffered from chronic hip joint pain. There were 18 patients of avascular necrosis of hip (AVN) 67% of whom were affected bilaterally 15 patients of degenerative arthritis(DA), 33% bilaterally; one patient of tuberculous arthritis rheumatoid ar-thritis and traumatic arthritis respectively. Comparison of th staging by means of the CT and plain film showed good correlation between the two methods. The CT findings of the AVN and OA were also compared; cres-cent sign or fissure loss of congruity and loss or change of normal asterisk sign were more commonly seen in AVN, Acetabular change especially associated cystic appearance osteophytes formation and joint narrowing were more frequent in OA. CT showed primary and secondary change of AVN. and OA more clearly without confusion than plain film. We think that CT can be helpful in evaluation and understanding of each disease process and differentiation of the two lesions in difficult cases.