Background: Onychomycosis is a fungal infection of nail unit. Tinea unguium is dermatophytic nail infection. common dermatophytes causing onychomycosis is Trichophyton rubrum. Onychomycosis increase in frequency with age, amongst them adult males are more frequently affected than females. There are various topical and systemic antifungal agents available for onychomycosis. Despite this it is difficult to treat onychomycosis as higher local concentration of drug is required for clearing the infection and it is difficult to achieve. Aim and objectives: To ascertain efficacy of fractional carbon dioxide laser in onychomycosis. To evaluate fractional carbon dioxide laser's effectiveness in total clearance of onychomycosis from nails. Materials and methods: Methods: 100 patients of clinically diagnosed onychomycosis were selected. All patient’s KOH smear examination was done by collecting samples from scrapings of nail material. All patients were given systemic antifungals along with topical antifungals. Laser sittings had been done at an interval of 1 month. Total 6 monthly sittings were done. Topical lignocaine hydrochloride 2% w/v gel were applied for 20-30minutes before giving laser therapy. Standard digital photographs were taken before initiating the therapy and then repeated monthly. After completion of 6 months all patients were followed up for 9 months with an interval of 3 and 6 months. Results: At 6 months after completion of 6 sittings of CO2 laser 68 patients had complete response, 16 patients had significant response, 8 patients had moderate response, 8 patients had no response at 6 months of therapy. Limitations: Small population size, absence of control group, mycological culture was not performed were the main limitations of our study. Conclusion: Fractional carbon dioxide laser is effective in treating onychomycosis along with topical and systemic antifungals and it has minimal side effects. Keywords: Onychomycosis, fractional carbon dioxide (CO2) laser.