AIM: To identify the predisposing factors, causative fungi and to improve the facilities for the laboratory diagnosis of fungal keratitis. METHODS: Two hundred and forty eyes of 240 patients of clinically suspected microbial corneal ulcer were included in the study. Data was collected through history and slit lamp examination. Using standard techniques, corneal scraping was performed.A portion of each scraping was examined by direct microscopy for the presence of fungi, bacteria and acanthamoeba by using 100g/L potassium hydroxide and also by Gram and Giemsa stainings. Another portion was inoculated directly on the surface of solid media such as blood agar, Mac-Conkey agar, chocolate agar and Sabouraud agar in C-shaped streaks for culture. RESULTS: A total of 240 patients with suppurative corneal ulcer were enrolled in the study, out of which fungi were identified in 84 (35%) patients. Of these, 48 (57.1%) were males and 36 (42.9%) females. The age ranged between 22-80 years. Sixty patients (71.4%) belonged to rural population and twenty four (28.6%) to urban population. Trauma with vegetative material was the most frequent cause noted in eighteen (21.4%) patients. Peak incidence was in the months of October-November. Out of 84 eyes with fungal keratitis, fungi alone were the etiologic agents in 74 (80.10%) cases and bacteria with fungi were identified in 10 (11.90%). The most frequently isolated organism was Candida albicans which was found in 66 (78.6%) patients. CONCLUSION: Fungal keratitis is the leading cause of infective corneal ulcer and Candida albicans being the most commonly isolated pathogen in the patients belonging to Southern Pakistan. The direct microscopic examination with potassium hydroxide 100g/L method is a simple, rapid, inexpensive and reliable method in the diagnosis of this infection.