OBJECTIVE To compare the effects of bifocal versus trifocal diffractive intraocular lens (IOL) implantation on visual quality after phacoemulsification in patients with cataracts. METHODS Eighty-eight eyes from 63 patients were analyzed. Trifocal (AT LISA tri 839MP), bifocal (AcrySof IQ ReSTOR) and bifocal (Tecnis MF ZLB00) IOLs were implanted into 53, 18, and 17 eyes, respectively. Uncorrected distance, intermediate and near visual acuity, refractive errors, contrast sensitivity, and patient satisfaction were measured at 1 week and 1 month after surgery. Refractive error was converted to a spherical equivalent and compared to predicted refraction calculated by IOL calculation formulas. RESULTS Uncorrected distance, intermediate, and near visual acuity did not differ significantly between groups. One month after surgery, the mean refractive errors were -0.07 diopters (D) in the AT LISA tri 839MP group, +0.18 D in the AcrySof IQ ReSTOR group, and +0.31 D in the Tecnis MF ZLB00 group (p < 0.001). The predictive accuracy of IOL calculation formulas did not differ between groups. Contrast sensitivity, satisfaction, and spectacle independence in the trifocal group were comparable with those of the two bifocal groups. CONCLUSIONS Trifocal IOL and two different types of bifocal IOL implantation were all effective for improving visual quality, although refractive error in patients with trifocal IOL shows myopic tendencies.