Introduction: Misconceptions and inadequate knowledge remains significant barrier towards prevention and control of diabetes in developing countries. Epidemiological shift of diabetes towards children makes mothers potential agents for any drive that targets diabetes. Objective: To assess knowledge and perception of mothers of under five children regarding etiology of Type-II Diabetes Mellitus. Material and Methods: Present hospital based cross-sectional study was conducted among 200 mothers of under five children attending Paediatric OPD of Agartala Govt. Medical College between May-June, 2012. Data was collected using a pre-designed questionnaire and information on socio-demographic characteristics, basic knowledge of mothers about diabetes and their perception regarding aetiology of Type-II DM was obtained. Data was analyzed using SPSS software version 17.0. Results: 12% and 7.5% mothers respectively believed that only old people and males suffer from diabetes. 73% mothers opined that diabetes can be prevented. 10.5% and 12% mothers believed that diabetes is contagious and caused by past sins. 39.5% mothers suggested that consumption of more sugar causes diabetes. Ethnicity was strongly associated with overall knowledge of mother regarding diabetes (Bengali mothers had more knowledge compared to tribal mothers). Knowledge of mothers regarding etiology of diabetes was associated with their ethnicity, type of family and occupation. However, caste, education, and family H/O of diabetes was not associated with knowledge regarding etiology of diabetes among respondent mothers. Conclusion: Knowledge and perception of mothers regarding diabetes was good, though inappropriate at times. Various misconceptions regarding etiology of diabetes, especially among tribal mothers, need to be addressed in the study area.