The authors report on a randomised, multicentre clinical trial comparing the outcomes of Tecnis ZM900 diffractive multifocal intraocular lenses (IOL) versus monovision with Akreos AO monofocal IOL (dominant eye targeted for emmetropia and non-dominant eye targeted for -1 to -1.50 dioptre myopia). A total of 212 patients with bilateral cataract and no other ocular pathology were randomised to either multifocal IOL or monovision. One hundred and eighty-seven patients (88%) returned for assessment four months after surgery. There was no significant difference between the two groups in terms of binocular distance visual acuity. However, the multifocal IOL group performed worse for intermediate distance vision, and the monovision group performed worse for near vision. More patients in the multifocal IOL group achieved spectacle independence (71.3%) compared to the monovision group (25.8%). Patients in both groups were highly satisfied with their visual outcomes, but the multifocal IOL group had higher levels of symptomatic dysphotopsia symptoms. In the first postoperative year, six patients (5.7%) in the multifocal IOL group underwent IOL exchange (four bilateral; two unilateral) mainly due to dissatisfaction with image quality. No patient in the monovision group underwent IOL exchange. This is a well-conducted randomised clinical trial, which confirms both the benefits and disadvantages of multifocal IOLs compared to monovision.