Avascular necrosis of the femoral head is the most serious complication after closed reduction in developmental dysplasia of the hip. Although arthrography has a well-established role in the treatment of developmental dysplasia of the hip, its use is not universal. A prospective study was conducted to compare the incidence of avascular necrosis after closed reduction in developmental dysplasia of the hip performed with and without arthrography in 85 patients, with a minimum of 5 years follow up. Arthrographic criteria were evaluated including lateralization of the femoral head and the type of limbus encountered. Hips treated by closed reduction based on arthrographic evaluation had significantly less incidence of avascular necrosis when compared with those treated by closed reduction without arthrographic guidance. Closed reduction with lateralization of more than 4 mm, and those hips with an inverted limbus were associated with an increased risk of avascular necrosis.