The diagnosis of occipital plagiocephaly has remained a complex and controversial issue in the field of craniofacial surgery. Over the past 30 years, numerous studies have been published describing the management and treatment for 'posterior plagiocephaly', 'plagiocephaly without synostosis', 'deformational plagiocephaly' and 'occipital plagiocephaly', with surgical 'correction' being chosen as the primary modality of treatment irrespective of the patency status of the lambdoid sutures. Two hundred and four patients with unilateral occipital plagiocephaly have been seen at the Australian Craniofacial Unit over the past 16 years. Each patient was evaluated by a craniofacial surgeon, paediatric neurosurgeon and paediatric geneticist. All children underwent plain radiographs of the skull to define the sutural anatomy. In those patients where the sutural anatomy was equivocal, 2-D and 3-D CT scans were performed. Only two of the 204 patients (approximately 1%) manifested the clinical, radiographic and pathological features of true unilambdoid synostosis. There was radiographic evidence of sutural fusion on plain films, 2-D and 3-D CT scans. Pathology specimens showed bony sutural fusion. Two hundred and two patients presented with unilateral occipital deformities and patent sutures on radiography. These patients with occipital plagiocephaly in the absence of true synostosis were initially managed conservatively (head positioning, and physiotherapy in those patients with torticollis). Those patients who underwent surgical correction in infancy (21/204) included patients with severe plagiocephaly not responding to conservative therapy (19/204) and the two patients with true unilambdoid synostosis (2/204).One hundred and ninety-one of the total patients (94%) were noted by their parents to have acceptable improvement in their head shape. Thirteen patients were seen within the past year and are too early to assess. Two surgical patients (one fronto-orbital advancement, one occipital craniectomy) and one patient followed conservatively were judged by their parents to be without notable improvement. In our series it is apparent that the majority of cases of occipital plagiocephaly are not secondary to true synostosis and can be managed by conservative positional measures.