The aim of this study was to assess the therapeutic efficacy of osteopathic treatment in infants with postural asymmetry. A randomized clinical trial of efficacy with blinded videoscoring was performed. Sixty-one infants with postural asymmetry aged 6 to 12 weeks (mean 9wks) were recruited. Thirty-two infants (18 males, 14 females) with a gestational age of at least 36 weeks were found to be eligible and randomly assigned to the intervention groups, 16 receiving osteopathic treatment and 16 sham therapy. After a treatment period of 4 weeks the outcome was measured using a standardized scale (4-24 points). With sham therapy, five infants improved (at least 3 points), eight infants were unchanged (within 3 points), and three infants deteriorated (not more than -3 points); the mean improvement was 1.2 points (SD 3.5). In the osteopathic group, 13 infants improved and three remained unchanged; the mean improvement was 5.9 points (SD 3.8). The difference was significant (p=0.001). We conclude that osteopathic treatment in the first months of life improves the degree of asymmetry in infants with postural asymmetry.