One hundred consecutive infants who presented with occipital plagiocephaly over 15 years were analyzed retrospectively to determine results of both surgical and nonsurgical management. Eighteen infants who showed obvious progression of their deformity or radiological signs of fusion of the lambdoid suture had surgical resection of one or both lambdoid sutures and the remaining 82 infants were treated nonsurgically with physical therapy and advice on sleeping position. Of the 18 surgical cases 9 were found at operation to have true lambdoid synostosis, 7 had marked internal ridging of the lambdoid suture and 2 had an open suture. After a mean follow-up period of 6 months all parents of the 82 children treated nonsurgically were satisfied with their child's cosmetic appearance: 63% showed improvement in their plagiocephaly and 27% stabilized. There were no surgical complications in the 18 operative cases, all of whom had a good cosmetic result. From these results we conclude that the majority of infants referred to neurosurgeons with occipital plagiocephaly can be successfully managed nonsurgically. A small proportion of cases (18% with radiological signs of fusion or pronounced ridging of the suture) appeared to benefit from surgery. The clinical, radiological and pathological differentiating features of the surgical and nonsurgical cases are discussed.