Background Multimorbidity among older adults is an increasing challenge for health systems. Compared to a single disease condition, multimorbidity lowers the quality of life and experience higher hospital admission and health care expenditure. Although multimorbidity has gained global attention, it remains a less studied area in Nepal. Our study aimed to estimate the prevalence of major chronic diseases and multimorbidity among older adults in rural Nepal and examine the associated socioeconomic and behavioral risk factors.Methods We analyzed data of 794 Nepalese older adults recruited using a multi-stage cluster sampling approach in two rural setting of Sunsari and Morang District of Nepal. This was a cross-sectional study, conducted between January to April 2018. Socio-demographics and health conditions data [ Osteoarthritis, Cardiovascular diseases (CVD), Diabetes, Chronic Obstructive Pulmonary Diseases (COPD) ] were collected through the help of trained research assistants using a validated questionnaire. The correlates of multimorbidity were examined using mixed-effects logistic regression.Results 48.9% of the participants had at least one chronic condition, and 14% were multimorbid. The prevalence of individual conditions were osteoarthritis- 41.7%, CVD- 2.39%, diabetes- 5.29%, and COPD- 15.7%. In the adjusted model, older adults aged 70-79 years, those from underprivileged Madhesi and other ethnic groups, without a history of alcohol drinking, and those physically inactive, were significantly associated with multimorbidity.Conclusion Our study found a sizeable proportion of the older adults had multimorbidity in our studied population. This prevalence of multimorbidity and its socioeconomic and behavioural correlates, need to be addressed through multi-level preventive strategies, including clinical guidelines and the development of a multidisciplinary workforce to address the needs of the multimorbid older adults.