Plagiocephaly may result from cranial deformation, craniosynostosis, congenital asymmetry syndromes, osteogenesis imperfecta, or altered muscle tone. The 1992 AAP recommendation that infants sleep on their backs or sides in order to help prevent SIDS has increased the incidence of plagiocephaly recently. Few patients experience improvement in cranial symmetry without intervention, though some infants undergo neurosurgical correction, most patients with nonsyndromic, nonsynostotic plagiocephaly respond to early conservative management, consisting of neck-stretching and head-turning exercises, with repositioning of the infant's head during sleep. Helmet therapy is utilized for severe deformation of the skull at six months of age, and for those cases in which conservative management has failed. The objectives of conservative therapy are to maximize the neck range of motion and vertical head position. Over the past eight years, we have evaluated 70 cases of plagiocephaly referred by their pediatricians: 19 patients had mild cranial asymmetry and were successfully treated with conservative management, 14 cases were moderately severe and 5 were successfully treated with conservative management, 9 patients failed to follow-up, 9 additional cases failed conservative management and were treated with helmet therapy, and the remaining 36 patients had severe plagiocephaly: 30 were recommended for helmet therapy, 6 were too old to benefit from helmet therapy, 4 were dropped from the study for failure to follow-up, and 8 cases had an underlying syndrome(asymmetry associated with vascular malformation, post-op craniosynostosis, and type 3 OI). Two patients fitted with helmets after age one year experienced minimal benefit after long-term therapy. The rest experienced marked improvement from helmet therapy. Maximal benefits from conservative therapy were achieved when treatment was instituted early in infancy, particularly for mild to moderate cases. Those with severe plagiocephaly achieved maximal benefits when helmet therapy was instituted prior to age 7 months and accompanied by conservative management measures.