Purpose: To report the efficacy and safety of intrastromal corneal ring segment (ICRS) implantation using a femtosecond laser in the management of advanced keratoconus. Setting: Private laser center, Toronto, Ontario, Canada. Method: In this retrospective nonrandomized study, Intacs SK ICRS were implanted using an IntraLase femtosecond laser in eyes with moderate to severe keratoconus. Evaluation included uncorrected (UDVA) and corrected (CDVA) distance visual acuity, manifest refraction, slitlamp examination, corneal topography, and wavefront analysis of higher-order aberrations. Postoperative visits were at 1, 7, and 30 days and 3 and 6 months. Results: The study evaluated 10 eyes of 8 patients with a mean age of 28 years (range 21 to 42 years). The mean UDVA was significantly better 6 months postoperatively than preoperatively (0.66 logMAR ± 0.21 [SD] versus 1.19 ± 0.57 logMAR) (P = .004), as was the mean CDVA (0.25 ± 0.15 logMAR versus 0.51 ± 0.20 logMAR) (P = .018). The mean spherical equivalent refractive error was -8.08 diopters (D) preoperatively and -5.03 D at 6 months (P = .65); the mean refractive astigmatism, -5.05 D and -3.90 D, respectively (P = .22); and the mean simulated keratometry value, 57.94 D and 50.07 D, respectively (P = .15). The mean total aberration improved significantly, from 13.48 ± 4.64 μm preoperatively to 9.42 ± 1.80 μm postoperatively (P = .007). There were no complications. Conclusion: Implantation of ICRS for advanced keratoconus was safe and effective, leading to significant improvement in UDVA, CDVA, and total aberrations. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.