The authors report on the long-term outcomes in a prospective case series of patients with keratoconus undergoing corneal collagen cross-linking (CXL) treatment. Thirty-two patients (40 eyes; mean age 22.5+/-5.5 years) with Grade I, II and III progressive keratoconus were recruited for this study. For the CXL treatment, the corneal epithelium was first removed before riboflavin 0.1% was instilled every three minutes for 30 minutes. The eye was then checked at the slit-lamp to confirm penetration of the riboflavin. Ultraviolet irradiation was done with the device (wavelength 370nm, width 9mm) placed at a perpendicular distance of 5cm from the eye for a total of 30 minutes, during which riboflavin instillation was continued at three minute intervals. After irradiation, the eye was irrigated with sterile balanced salt solution and a soft bandage contact lens was placed. Post-procedure medications included chloramphenicol 0.5%, betamethasone 0.1% and preservative artificial tears. Patients were examined at one month, three months, six months, one year, two years, four years and five years after CXL treatment. Over the five year study period, Pentacam scan results showed the mean maximum keratometry and mean keratometry to decrease slightly (non-significant). CCT increased significantly up to 12 months after treatment, but no change was seen after that. Mean anterior elevation and mean posterior elevation increased at six months and one year, but decreased thereafter until five years. No significant long-term adverse effect was noted. The results from this study suggest that CXL is a safe way of stopping keratoconus progression over the long-term, at least in this cohort of patients. The long-term results from the larger trials are keenly awaited.