MRI findings for 51 hips in 45 pediatric patients (mean age 2.3 years; range, 1.1-4.1 years) with suspected acetabular dysplasia or residual subluxations were analyzed retrospectively. We attempted to predict the growth of osseous acetabulum and future acetabular coverage on MRI performed at 2 years of age. The cut-off value of the cartilaginous angle was 18° for the cartilage acetabular index and 13° for the cartilage center edge angle. However, follow-up assessments to monitor the progress of changes in the congruity between femoral head and acetabular development are important.