This prospective clinical study compared the corneal astigmatism before and after pterygium excision surgery with conjunctival autograft transplantation. The study included 37 eyes of 37 patients diagnosed with pterygium. All participants underwent pterygium excision with conjunctival autograft transplantation and were examined preoperatively and on the first and third month post-intervention. Comprehensive ophthalmic examination was done and measurements included: pterygium size, uncorrected and best corrected visual acuity and corneal astigmatism. Preoperative and postoperative values were compared using the nonparametric Wilcoxon signedranks test. The mean pterygium horizontal length was 2.18 mm (range 1-4 mm). A statistically significant correlation was observed between the pterygium length and preoperative astigmatism. The mean corneal astigmatism preoperatively was 1.26 § 1.18 D and decreased to 0.84 § 0.73 D three months after the intervention (p < 0.001). The mean UCVA (uncorrected visual acuity) preoperatively was 0.75, improving to 0.77; the mean BCVA (best corrected visual acuity) before surgery was 0.86, improving to 0.87 after the procedure. These results demonstrated that the amount of induced astigmatism increased in proportion to the size of the pterygium increase. The corneal astigmatism tended to decrease significantly following pterygium excision with conjunctival autograft transplantation.