Background& Objective: Onychomycosis is a frequent nail disease caused by dermatophytes, yeasts, and non-dermatophyte molds. Far more than being a simple cosmetic problem, infected nail serves as a chronic reservoir, which can give rise to repeated mycotic infections. This study aim to identify the common fungal species which are responsible for onychomycosis in clinically suspected patients of onychomycosis in Dermatology and Venereal Diseases Hospital in Damascus between October 2010 and July 2011. Materials & Methods: Both direct microscopy and culture of the nail material were performed to identify the causative fungi of onychomycosis. Results: Culture positivity was obtained in 65 of the 76 clinically suspected samples, etiological fungal agents were (%61.5) dermatophytes, (24.6%) yeasts, and (13.9 %) non-dermatophyte molds . The isolated fungal species were (43.1%) Trichophyton Rubrum and (16.9%) T. Interdigitale (1.5%) T.Verrucosum Aspergillus Versicolor which was the most frequent non dermatophyte molds. Females were affected in fingernails more frequently than males, while males were affected in toenails more frequently than females, and in both sexes those most infected were between 20-40 years of age. Conclusion: Dermatophytes, in particular T. rubrum, but also T. Interdigitale, are the most frequently isolated causative agents in onychomycosis in patients seen in Dermatology and Venereal Diseases Hospital in Damascus . In addition, yeasts may be isolated relatively frequently, while molds are uncommon.