In the past two decades, research on the sociology of diagnosis has attained considerable influence within medical sociology. Analyzing the process and factors that contribute to making a diagnosis amidst uncertainty and contestation, as well as the diagnostic encounter itself, are topics rich for sociological investigation. This paper provides a reformulation of the sociology of diagnosis by proposing the concept of 'social diagnosis' which helps us recognize the interplay between larger social structures and individual or community illness manifestations. By outlining a conceptual frame, exploring how social scientists, medical professionals and laypeople contribute to social diagnosis, and providing a case study of how the North American Mohawk Akwesasne reservation dealt with rising obesity prevalence to further illustrate the social diagnosis idea, we embark on developing a cohesive and updated framework for a sociology of diagnosis. This approach is useful not just for sociological research, but has direct implications for the fields of medicine and public health. Approaching diagnosis from this integrated perspective potentially provides a broader context for practitioners and researchers to understand extra-medical factors, which in turn has consequences for patient care and health outcomes.