Objectives The objective of this study was to compare the effect of single clear corneal incision (CCI) on the steep axis with opposite clear corneal incisions (OCCIs) on pre-existing regular corneal astigmatism in cataract patients having phacoemulsification. Background Correction of pre-existing regular astigmatism in phacoemulsification. Patients and methods This randomized prospective clinical study included 30 eyes of 30 cataract patients with corneal regular astigmatism greater than 1 D. The patients were randomly divided into two groups, each group involving 15 eyes. Paired 3 mm CCI were made on the steep axis in Group A and single in Group B. Preoperative evaluation included uncorrected visual acuity, refraction, best-corrected visual acuity, applanation tonometry, fundus examination, biometry, keratometry, and corneal topography. The vertical axis was marked before peribulbar anesthesia was given and routine phacoemulsification was performed through a 3-mm CCI on the steep axis. An additional opposite 3-mm self-sealing CCI was made opposite to the first one in Group A. Patients were examined 2, 4, and 8 weeks postoperatively. Visual acuity, refraction, keratometry, and corneal topography were used to evaluate the improvement. Results The mean preoperative and postoperative topographic corneal astigmatism was 1.95 D ± 0.83 (SD), 0.59 D ± 0.47 (SD) and 1.93 D ± 0.51 (SD), 1.53 D ± 0.62 (SD), respectively, in Groups A and B. There was a significant difference between the mean values of astigmatism in the two groups postoperatively. The mean surgically induced astigmatism, measured by a vector-corrected method, was 1.2 ± 80.11 D and 1.09 ± 0.13 D in Group A and Group B, respectively ( P = 0.00). The mean values of best-corrected visual acuity were 0.11 ± 0.13 in Group A and 0.22 ± 0.15 in Group B postoperatively ( P Conclusion OCCIs on the steep axis were more effective than single CCI in the correction of mild to moderate pre-existing corneal astigmatism.