AIM: To evaluate clinical outcomes of unilateral implantation of a diffractive multifocal intraocular lens (IOL) in patients with contralateral monofocal IOL. METHODS: Twenty-two patients who already had implantation of a monofocal IOL in unilateral eye underwent implantation of a diffractive multifocal IOL in contralateral eye were enrolled. After 1, 6, and 12mo, uncorrected and distant corrected distant visual acuity (UCDVA and DCDVA), uncorrected and distant corrected intermediate-visual acuity (UCIVA and DCIVA), uncorrected and distant corrected near visual acuity (UCNVA and DCNVA), and contrast sensitivity were obtained. Halo/glare symptoms, spectacle dependence, and patient satisfaction were also evaluated. RESULTS: The mean age was 67.86±7.25y and the average interval between two IOL implantations was 645.82±878.44d. At 1mo, binocular UCDVA was lower than 0.20 logMAR in 76% of patients (mean 0.12±0.13 logMAR), which increased to 90% by 6 and 12mo. The binocular UCDVA was significantly better than the monocular results (P<0.05) at 1, 6, and 12mo. Additionally, UCNVA was lower than 0.40 logMAR in 82% of patients, increasing to 90% by 6 and 12mo. Mean UCNVA in the multifocal IOL implanted eye was statistically significantly better than that in the monofocal IOL implanted eye (P<0.05) at 1, 6, and 12mo. About 5% of patients at 1 and 6mo, reported “severe glare or halo”. Patient satisfaction rates were 95% and 91% at 6 and 12mo, respectively. CONCLUSION: Unilateral implantation of multifocal IOL in patients with a contralateral, monofocal IOL implantation results in high patient satisfaction rate, with low severe glare or halo rate during follow-up. It can represent a good option for patients who have previously had a monofocal IOL implantation regardless of two year interval duration between two IOL implantations.