Nested case-control study was carried out to assess nutritional status and identify other risk factors among people with major mental disorders (schizophrenia and bipolar), in Meskan and Marako district from Dec. 2001 to Feb. 2002. Data were collected on sociodemographic factors, lifestyle, and nutritional, reproductive health and dietary patterns. Complete data obtained from 434 cases and equal numbers of controls matched by sex, age in five years range and residence, on one to one ratio. The cohort list of Mental Health Research Project (MHRP) was used to identify all cases, and controls were selected from the nearest neighbors by frequency matching. Cases and controls were compared by socio-economic, nutritional, reproductive, and dietary characteristic. Major mental disorders were positively significantly associated with unmarried (OR=1.88 with 95%CI 1.33, 2.66), illiterates (OR=1.91 with 95%CI 1.04,2.29), Muslims (OR=1.50 with 95%CI 1.27,2.88), not having cattle (OR= 2.59 with 95%CI 1.47, 4.55) while owning a radio (OR= 0.66 with 95%CI 0.41,0.88), and spending less time on job (OR= 0.29(0.22, 0.40) were negatively significantly associated. 'Khat' chewing and cigarette smoking were also positively significantly associated (OR=2.68 with 95%CI 1.53,4.69 and OR=2.32 with 95%CI 1.37,3.90) respectively with major mental disorders. Adult malnutrition was positively significantly (OR=4.08 with 95%CI 1.42,11.74) and weight (OR=1.55 with 95%CI 1.08,2.24) associated with major mental disorders. Cases and controls were not different on micronutrient deficiencies, reproductive and dietary characteristics. The results of this study help the project managers and others in designing effective intervention strategies to improve the health of the community in general and those with mental health problems in particular. vii