The authors evaluated inferior oblique (IO) muscle belly transposition to correct mild to moderate IO overaction with small primary position hypertropia. They reviewed 10 patients aged 6-35 years (mean 18.6 years). Aetiologies were mild unilateral superior oblique (SO) palsy for eight and two with primary IO overaction. Surgery involved unilateral IO belly transposition for all and two had additional horizontal surgery. The surgery involved suturing of the entire body of IO to sclera 5mm posterior to the temporal insertion of the inferior rectus (IR) muscle. Follow-up was 6-12 months. Hypertropia in primary position reduced from 3.30±0.48PD to 0.10±0.32PD whilst hypertropia in lateral gaze reduced from 8.60±2.63PD to 0.60±1.35PD. IO overaction grade reduced from 1.5±0.71 to 0.1±0.32. Abnormal head posture improved in all cases. There were no overcorrections or anti-elevation syndrome postoperatively. The authors conclude this procedure effectively weakens the IO and corrects small angle primary position hypertropia and, as such, is a useful addition to surgical options.