AIM: To compare simultaneous corneal collagen cross-linking (CXL) with intracorneal ring segment (ICRS) implantation versus successive ICRS followed by CXL and detect the impact of the timing of CXL after ICRS implantation in the successive method. METHODS: This is a retrospective study of the records of three groups of patients. Group 1 of 28 patients were operated on with simultaneous ICRS implantation and CXL, group 2 of 32 patients had ICRS implantation followed by CXL after 1mo, and group 3 of 38 patients had ICRS implantation followed by CXL after 3mo. The three groups had follow-up visits after 6, 12, and 24mo. RESULTS: The preoperative data, age, and gender differences among 3 groups revealed no significant differences. The postoperative spherical equivalent and best-corrected visual acuity were improved significantly in all groups compared to the baseline, which were more evident in groups 1 and 2. The differences between preoperative and postoperative mean values of mean of K readings (Km) and maximum K reading (Kmax) at 6mo were 4.66 and 4.1 D in group 1, 4.43 and 4.64 D in group 2, but 3.2 and 3.4 D in group 3, respectively. The spherical aberrations and the vertical coma showed significant postoperative changes in all groups, and trefoil showed nonsignificant changes. CONCLUSION: Simultaneous and sequential ICRS implantation and CXL at 1mo has similar Km and Kmax better postoperative changes than when both surgeries were done at three-month intervals.