Summary:The past decade has seen a change in attitude about hip sonography from skepticism to wide acceptance as a standard imaging examination. The infant hip sonogram provides accurate, reliable, and reproducible information in the course of diagnostic evaluation and treatment. Because this method can assess hip instability, acetabular morphology, and efficacy of treatment, it has taken the place of contrast arthrography. Moreover, the hip sonogram is less costly and does not require sedation, ionizing radiation, or arthrotomy. Decisions regarding the need for treatment, confirmation of successful reductions, and understanding of the evolution of acetabular morphology are all facilitated by proper performance and accurate analysis of hip sonography.