AIM:To evaluate the epidemiological and etiological factors of microbial keratitis seen in tertiary hospitals in West and East Malaysia.METHODS:A total of 207 patients were enrolled.Patients referred for microbial keratitis to Sungai Buloh Hospital and Kuala Lumpur Hospital in West Malaysia and Queen Elizabeth Hospital and Kuching General Hospital in East Malaysia were recruited.Risk factors were documented.Corneal scrapings for microscopy and culture were performed.RESULTS:The most common risk factor in West Malaysia was organic trauma (28.5％) followed by non organic trauma (18.3％);27.7％ of trauma cases was work related with 34.2％ involving male foreign workers.The most common risk factor in East Malaysia was contact lens wear (32.9％).Pseudomonas aeruginosa was the most common organism isolated in both places.The most common fungal pathogen in West Malaysia was Fusarium spp representing 60％ of all positive fungal cultures.CONCLUSION:In West Malaysia organic trauma was the most common risk factor seen in public hospitals here whereas,contact lens wear was the most common risk factor in East Malaysia (P＜ 0.05).Fungal keratitis was more commonly seen in West Malaysia.