Purpose: To evaluate changes in corneal hystresis and corneal resistance factor in keratoconic eyes at 1 and 6 months after collagen cross linking.Methods: Thirty eyes of 22 patients with mean age 24.56 ± 3.79 years with progressive keratoconus were treated with UVA– riboflavin CXL and assessed with the Ocular Response Analyzer (ORA) that measured corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann correlated intraocular pressure (IOPg), and corneal compensated intraocular pressure (IOPcc). Patients were assessed with ORA preoperatively, at 1 and 6 months after treatment. Postoperative measurements at each visit were compared with preoperative values.Results: CH was decreased after cross linking treatment, with the difference statistically insignificant at 1 and 6 months (p value = 0.61 and 0.198 respectively). CRF was elevated at 1 and 6 months after CXL and was statistically significant at 6 months (p = 0.005). Conclusion: After collagen cross linking no significant change in corneal hystresis occurs at 1 and 6 months. Increase in corneal resistant factors occurs and was statistically significant at 6 months