Arthrography is useful method to evaluate obstruct factors and the congruity of the femoral head for developmental dysplasia of the hip. We usually use an air injection to ascertain whether the needle is accurately insert intraarticularly, because leakage of the contrast medium may make it difficult to identify intraarticular structure in the hip joint. We report the experience the case that suspected air embolism by air injection in the arthrogram. An air injection for arthrography must be avoided the case of infants. To confirm that a needle is correctly inserted intraarticularly, it is preferable to inject saline. Alternatively, it may be suitable to use sonography for confirming the position of the needle for arthrography.