Introduction:The knowledge about the hip joint space width which is formed between the head of femur and acetabulum is essential for radiological practice in identifying the pathologies of hip joint like osteoarthritis and in orthopaedic surgeries. Aim:Determination of mean values of hip joint space width. Materials and Methods:Normal plain radiographs of pelvis with bilateral hip joints – AP view of both males and females between the 20 to 50 years of age were used for study. A total of 200 xrays (100 males and 100 females) were included in the study. Inclusion criteria: a) Patients complaining of pain in hip, who had no joint pathology defined on the basis of radiological examination. b) Patients of age group 20-50 years.c)Patients without any deformity of hip joint. Exclusion criteria:a)Patients having history of pathologies like Osteoarthritis, Tuberculosis, Fractures around hip joint. b) Patients having history of Surgical intervention around this area. Observations:All the 200 xrays belonged to adult (20 to 50 years) population.The overall mean hip joint space width of all the 200 subjects on the right side was 4.44 + 1.18 mm. The overall mean hip joint space width of all the 200 subjects on the left side was 3.97 + 0.91 mm. The overall mean hip joint space width at the superolateral margin of all the 100 males was found to be 4.95+1.25 mm on the right side while on the left side it was found to be 4.27+ 1.00 mm. The overall mean hip joint space width at the superolateral margin of all the 100 females was found to be 4.65+1.32 mm on the right side while on the left side it was found to be 4.06+ 0.93 mm. The overall mean hip joint space width at the apical region of all the 100 females was found to be 4.33 + 1.10mm on the right side while on the left side it was found to be 3.81 + 0.93mm . The overall mean hip joint space width at the apical region of all the 100 males was found to be 4.52 + 1.25mm on the right side while on the left side it was found to be 4.08 + 0.90mm. The overall mean hip joint space width at the superomedial margin of all the 100 females was found to be 4.03 + 1.03mm on the right side while on the left side it was found to be 3.67 + 0.84mm. The overall mean hip joint space width at the superomedial margin of all the 100 males was found to be 4.19 + 1.13mm on the right side while on the left side it was found to be 3.93 + 0.86mm. Conclusion: The results calculated provides important information regarding gender and side variations of hip joint space width for the radiologists, orthopaedic surgeons and anatomists. Radiological knowledge of hip joint space width will help the orthopaedicians in diagnosis and treatment of various clinical conditions like osteoarthritis. The data thus obtained can be used as a baseline for further studies in the departments of Anatomy, Radiodiagnosis and Orthopaedics.