Background: Onychomycosis is the commonly encountered problem especially in adults. Appears as a simple cosmetic problem infected nails, but have significant effect on patients emotional, occupational and social aspects, also serve as reservoir of mycotic infection and can give rise to repeated skin infections. Dermatophytes are the principal pathogens. Objectives: Isolation and identification of fungal agents causing onychomycosis and to study the predisposing factors with their clinical presentations. Methods: Appropriate samples from 50 patients with a diagnosis of onychomycosis were included in study for a duration of one year, from July 2012 to August-2013. Nails were collected in sterile black craft paper envelopes of 5x5 cms after disinfection and nail borings from nail bed. These were subjected to 20 to 40% KOH mount, routine Culture on SDA with antibiotics and cycloheximide. Isolates were identified based on colony morphology and biochemical reactions. Results: In a sample size of 50, dermatophytes were predominant agents 70.58% compared to non-dermatophytes 29.4%, 78% were males and 22% were females. In these cases distal and lateral sububgual onychomycosis (60%) was the most common clinical presentation followed by proximal subungual onychomycosis (20%). Total positive culture cases were 17 (34%), among which Trichophyton rubrum 41.17% was predominant followed by T.mentagrophytes 17.6%. Conclusion: Not all nail dystrophies are fungal in origin, an accurate laboratory diagnosis of onychomycosis is must, as been shows in this study. Dermatophytes were predominant etiological agents among which T.rubrum was most common Changing. Systemic and local predisposing factors were diabetes, anemia, traumatic injury, hands submerged in water for prolonged time.