The Duke Activity Status Index (DASI) is a validated questionnaire in English to assess the functional capacity (FC) of patients with cardiovascular disease (CVD). Aim: The aim of the study is to translate, cross-culturally adapt, and validate the DASI in Hindi. Observational validation study. Different translators translated the DASI into Hindi and then back-translated it into English. Validation for feasibility and psychometric properties of translated questionnaire was done on 200 adults, Hindi-speaking patients with CVD, who were advised exercise testing by a cardiologist. Internal consistency (Cronbach's α) and test-retest reliability (Pearson's correlation coefficient) were calculated. Construct (correlation with the Canadian Cardiovascular Society Classification [CCSC] for angina and exercise capacity with treadmill testing [TMT]) and content validity (time taken to fill the questionnaire, ease of understanding the questionnaire items, and comprehensibility) were calculated.P < 0.05 was considered significant. Results: The Cronbach's α for internal consistency was 0.78, which indicates adequate relatedness among the items of questionnaire, and the test-retest reliability was 0.65 (P < 0.05). A significant correlation between CCSC (r = -0.60) and TMT (r = 0.56) was found. The median time taken by the respondents to fill the questionnaire was 4 min. Of all the respondents, 95.74% of the respondents agreed that the Hindi questionnaire was easy to comprehend and 97.87% patients correlated the translated items to their daily physical activity. The Hindi translated and culturally adapted version of the DASI is reliable, valid, and feasible to assess the FC in the Hindi-speaking CVD patients.