Introduction: The prevalence of nonsynostotic skull deformities in children has increased considerably since the 1990s. The main cause of deformational plagiocephaly and brachycephaly seems to be supine position, as recommended for SIDS (sudden infant death syndrome) prevention. We therefore sought to answer the question: what is the natural history of this condition, and what evidence exists for treatment? Methods: We carried out a medline search (key words: plagiocephaly, brachycephaly) and analysed the results for definition, prevalence, measurement, natural history, physiotherapy and helmet therapy. Results: Deformational plagiocephaly and brachycephaly are common (point prevalence in infants more than 20%). Diagnosis is usually made by medical history and clinical examination. The degree of severity is subjective and no general consensus about measurement methods/severity grading exists. In view of the reported high prevalence, time spent in prone position („tummy time“) should be emphasized as an important preventive measure. Latest data point to a possible association between deformational skull deformities and neurodevelopmental delay, however longterm studies on that subject are lacking. Although physiotherapy and head positioning seem to be important in prevention and treatment, strong evidence for these interventions is likewise lacking. There are currently no prospective randomised studies of helmet therapy for the treatment of skull deformities. Conclusion: There is urgent need for well designed prospective studies to define which children require or would benefit most from physiotherapy and/or Helmet therapy.