BACKGROUND. Acute primary angle-closure glaucoma (PACG) is a severe disease requiring intensive and emergency treatment. Surgical peripheral iridectomy and laser peripheral iridectomy procedures are performed to decrease papillary block and create an opening for the aqueous humor to pass through the eye. However, the intraocular pressure (IOP) cannot be consistently controlled by peripheral iridectomy. Phacoemulsification can widen the anterior chamber angle, position the ciliary processes in eyes with PAC posteriorly and inhibit the acute angle closure. This procedure can control the intraocular pressure sustainably for a long period. The higher incidence of the acute angle closure glaucoma in Mongolia compared to other countries was the rationale of this study. MATERIAL AND METHODS. Medical records of 9 patients (9 eyes) with acute PACG, who had received phacoemulsification with intraocular lens implantation as initial management for medically uncontrolled high IOP, were analyzed in a retrospective chart review. IOP, visual acuity, anterior chamber depth (ACD) and the number of anti-glaucoma medications used were evaluated. RESULTS. The postoperative IOP was reduced in 9 eyes (100%). The mean preoperative IOP was 37.9 ± 13.0 mmHg, which decreased postoperatively to 11.0 ± 1.9 mmHg at day 1, 11.1 ± 2.1 mmHg at week 1, 11.1±2.0 mmHg at 2 weeks, 11.8 ± 1.9 mmHg at month 1, and 11.3 ± 1.4 mmHg at 3 months, which showed statistically significance (p < 0.001). The mean visual acuity improved from preoperative average of 0.04±0.03 to postoperative average of 0.17±0.24 at day 1, 0.45±0.26 at week 1, 0.54±0.31 at week 2, 0.56±0.34 at 1 month, and 0.57±0.33 (p = 0.001) at 3-months. There was functional success at month 3. СONCLUSION. Our outcome indicates that primary phacoemulsification with intraocular lens implantation lowered IOP and improved visual acuity significantly in patients with acute PACG. This is a safe and effective method of IOP control and can be considered a first line treatment option in managing patients with acute PACG and coexisting cataract.