This study focuses on the treatment of the muscle function imbalance and asymmetric head posture for infants with congenital muscular torticollis (CMT). The aim of this study was to compare treatment time for groups with different strategies for muscle function training. The treatment goal was to achieve a symmetric head posture. Thirty-seven infants were randomised to three groups. Group I was treated only with handling strategies. Group II got the same handling strategies but also received specific strength exercises. Group III received the same treatment as group II but was also provided with weekly training by a physiotherapist. Mean age at the start of treatment was 4.5 months of age, range 1-10.5. The possible effect of covariates was also investigated; age at the start of treatment, range of motion (ROM) in rotation of the neck, ROM in lateral flexion of the neck, the muscle function scale (MFS) score, plagiocephaly, and gender were analysed with ANCOVA. Thirty-one treated infants achieved symmetric head posture before the age of 12 months. Mean treatment time (3.5 month) did not differ significantly between the groups. All infants randomised to group I could stay in that group. The MFS score and age at the start of the treatment influenced treatment time (p?