Purpose: Corneal collagen cross-linking (CXL) is a promising method in the treatment of keratoconus (KCN); however, long-term results of this treatment modality are under-represented in the literature. In this article, we describe outcome of CXL in a cohort of patients after 4 years of follow-up. Materials and methods: CXL with corneal epithelium removal was done in patients with progressive clinical keratoconus. Full set of ophthalmic examination and scanning slit corneal topography were done for patients before intervention and on regular postoperative followup examinations. Results: One hundred thirty-two eyes of 66 consecutive subjects were enrolled in the study with a mean follow-up period of 48 months. Uncorrected distant visual acuity improved from preoperative value of 0.26 ± 0.21 to 0.36 ± 0.23 Snellen acuity in last follow-up exam (p=0.0008). Mean keratometry decreased from 46.18 ± 2.36 D before CXL to 45.6 ± 2.37D in last follow-up (p=0.0480). Similarly, maximum keratometric value were 49.05 ± 3.75 and 47.93 ± 4.14, in preoperative exam and at last postoperative visit, respectively (p=0.0226). Conclusion: CXL results in reduction of keratoconus progression and improvement of visual acuity in long-term follow-up.