Diabetic Mellitus is a reason for concern as it significantly increases one's risk of developing microvascular and macrovascular complications and adversely affects the quality of life (QoL). QoL is a term used to appraise the patient's functional capacity, psychological, social health and over all sense of wellbeing. For chronic illnesses like diabetes mellitus the therapeutic success is conventionally measured by disease-free and overall survival, and control of chief physical symptoms. Number of tools is available for assessing the quality of life in diabetes each with their advantage and disadvantages. The aim of this study was to design and test the reliability and validity of Modified Diabetes Quality of Life questionnaire (MDQoL-17) and to assess the quality of life of south Indian diabetic patients. The tool was developed and validated appropriately. The tool was translated into kannada for use in the local patients and appropriately validated for translation. The developed tool had appropriate reliability and internal consistency. Overall Quality of life of Diabetic patients was analyzed from the data collected of 100 patients and has shown moderate QoL by both the questionnaires. The QoL predicted by RAND-36, which consists of 36 questions and MDQoL-17, which consists of 17 questions, was almost the same. This showed that MDQoL-17 was good enough to predict the Quality of life as RAND-36. The QoLscore was correlated with demographic and other variables. This study showed that the developed MDQoL-17 questionnaire performed similar to the established RAND-36 and could be used as a tool to assess the quality of life in diabetic patients.