Since the beginning of the development of occupational science, occupational therapists have asked questions about its relationship with, contributions to, and research evidence produced useful to occupational therapy. To answer these questions with past and current research, I begin by reviewing basic scientific definitions, terminology, and conceptual models of health and occupation, and the early development of occupational science. Research on the essential elements of occupation is reviewed as a foundation for later translational research efforts. Finally, examples of occupation focused research evidence for occupational therapy practice is described. The need to understand the value of high quality non-traditional research evidence for optimal use in clinical reasoning is emphasized for future strength of the field of occupational therapy.