The prevalence of positional plagiocephaly is increasing. A systematic database search (Cochrane, MEDLINE, Embase, Cinahl and PEDro), critical appraisal and systematic evaluation of the quality of 14 selected studies show that the following are certain risk factors for the development of positional plagiocephaly: supine sleeping position, positional preference, one-sided handling of the child, male sex, delayed motor development, reduced neck mobility, too little "tummy time", firstborn, multiple births and premature children. Recommendations for prevention are provided.