This review aimed to synthesize current research evidence to determine the effectiveness of conservative interventions for infants with positional plagiocephaly. A systematic review was conducted, where papers were sourced from 13 library and internet databases. Research was included if published in English between 1983 and 2003. Level of evidence and quality of each paper was assessed to determine studies' magnitude of inherent bias. Results were synthesized in a narrative format and were considered with respect to homogeneity of participants, response rate, and outcome measures. Sixteen papers met inclusion criteria: 12 were case series and four were comparative studies. The methodological quality of the studies was moderate to poor, thus their results should be interpreted with caution. A consistent finding was that counterpositioning +/- physiotherapy or helmet therapy may reduce skull deformity; however, it was not possible to draw conclusions regarding the relative effectiveness of these interventions. Further investigation is required to compare the effect of helmet therapy with counterpositioning alone or when combined with physiotherapy. First, there is a need to develop an outcome measurement battery which incorporates psychometrically-sound measures from the perspectives of clinicians and patients.