INTRODUCTION The prevalence of early onset type 2 diabetes (Diabetes below the age of 45 years) is increasing worldwide. Transition in socio-economic position-i.e. Life Course Socio-Economic Transition (LSET) - may contribute to the development of early onset T2D through complex processes involving economic and occupational opportunities as well as individual life style choices. AIM To develop and validate the life course socioeconomic transition questionnaire and to know the association between life courses socioeconomic transition and early onset type 2 diabetes. MATERIALS AND METHODS This study follows sequential exploratory mixed method study design. It consists of one qualitative strand followed by two quantitative strands. Qualitative strand consist of in- depth interview among the community dwellers to develop a tool for measuring LSET. Two quantitative strands consist of the validation of the questionnaire by conducting cross-sectional survey among 200 randomly selected community dwellers and a hospital based case control study using the same questionnaire. RESULTS Those who have a history of lower SEP during his childhood period and enjoying higher SEP during his adulthood period have an increased risk for developing type 2 diabetes at their younger age (18-45 years). CONCLUSION This study will help to develop a validated life course socioeconomic transition questionnaire and application of that tool in an epidemiological study.