The purpose of the study was to investigate burnout among caregivers of patients with chronic physical illness. In this study both quantitative and qualitative research methods were used and data was collected from five different Govt. and non Govt. hospitals with purposive sampling. In the quantitative phase, participants were 365 and in qualitative phase, number of participants was 10. Socio-demographic questionnaire, Bangla form of Copenhagen Burnout Inventory and a topic guide were used in the present study. Quantitative data was analyzed by SPSS-20 and qualitative data was analyzed manually. Result shows that 28.2% caregivers of chronic physical illness have burnout problem and personal burnout rate is high than work burnout and client burnout. Significant differences of burnout have found between male and female, formal and informal caregivers where female and informal caregiver burnout rate is high than male and formal caregivers. The result also shows that there are significant differences of burnout among caregivers of six chronic diseases and also by care giving duration. Result also highlights some important contributory factors like lack of financial support, work overload, limited social life, irregular daily activity, worry about patient etc. On the other hand, some significant protective factors have found like love for patient, hope for patients recovery, sense of responsibility, religious belief, patients happiness, coping strategies etc. It can be concluded that caregivers are an important part of care giving and they need special attention to mitigate and prevent burnout problem.