The Ortolani maneuver is currently accepted as an accurate test to detect developmental dislocation of the hip. However, the clinical sign does not always correlate with the findings seen on ultrasound. The ultrasound-documented position of the femoral head was correlated with the result of the clinical Ortolani examination to better understand the value and validity of the Ortolani test. Two populations were compared: hips with a positive Ortolani sign and hips with a negative Ortolani sign but with an ultrasound-documented dislocated hip. In the Ortolani-positive group, there were 45 patients (53 affected hips), and in the Ortolani-negative group, there were 24 patients (25 dislocated hips). Position of the femoral head at rest, side of involvement, and sex showed no significant difference between the Ortolani-positive and -negative groups. Mean age of patients in the Ortolani-positive group was less (mean, 28 days) and was statistically different (P < 0.05) from those in the Ortolani-negative group (mean, 91 days). In conclusion, dislocated hips that show similar femoral head movement can produce an Ortolani-positive examination in a younger patient and an Ortolani-negative examination in an older patient. The classic clinical method described by Ortolani for detecting hip dislocation in which the thigh of the affected hip is abducted and the femoral head was thought to be reducing into the acetabulum can be erroneous. All Ortolani-positive hips were abnormal, as the sensation characteristic of a positive Ortolani examination may be felt without full reduction and, in some cases, with no reduction, as documented by ultrasound.