In the Philippines and in many other countries, not so many studies have been conducted with prisoners specifically on their protein and nutritional status. Thus, this study was conducted among adult male inmates in San Ramon Prison and Penal Farm, Zamboanga City, Philippines in January 2001 with the objective to determine the association between protein and energy intakes and nutritional status, among adult male inmates. The study was cross sectional and included 105 randomly selected adult male inmates. Data were collected using interview, anthropometries and biochemical assessments procedures. Results of the study evidently showed: the present protein and energy intakes and nutritional status of the inmates were good and it was reflected in the biochemical assessment. The diet of the inmates was sufficient with regard to total protein, calcium, iron vitamin A and riboflavin and very deficient in total energy, ascorbic acid, niacin and thiamin. With the exception of bananas no fruit has been served during the survey. Animal protein constitutes very low and most of their dietary protein source was derived from plant specifically green mug bean which was easily recognized by the inmates during the survey. In spite of good protein index based on biochemical assessment, the data findings also suggested that protein intake could still be improved by increasing the protein quality. Health and nutrition education should be focused and given attention as well. In conclusion, protein and nutritional status among adult male inmates in San Ramon Prison and Penal Farm were adequate based on anthropometric and biochemical assessment.