Background: Activities of daily living (ADL) deficit is a common and significant problem after any condition. Many scales are more focused on assessing the patients' independence or dependence but are less understood on the different parameters such as importance and values of activity, satisfaction, ability to cope up, completion, and time taken for the activity. These parameters are not well defined in many ADL assessments. Objectives: The purpose of this index was to evaluate ADL not only based on independence but also to understand the patients' values, adequacy, safety, standard, and finally, acceptability. Study Design: A prospective quantitative study was conducted. Methods: We conducted prospective, quantitative study and developed a new scale. Items were generated from a review of literature, semi-structured interviews of adult as well as geriatric patients and discussions with experts were carried out. The new instrument was piloted among 290 patients with neurological and orthopedic conditions. Content validity, internal consistency, and test-retest reliability were evaluated. Results: The new scale has good internal consistency: Cronbach's alpha = 0.984 and KR20 value = 0.97. Test–retest reliability (intra-class correlation coefficient = 0.87) was found to be good. Conclusion: Our research analysis indicates that Occupational Therapy (OT) ADL index is reliable for rating the Basic ADL skills for functional deficits in neurological and orthopedic conditions in adults. The OT ADL index may facilitate an objective assessment in the OT domains of basic ADL.