Coexistence of multiple chronic conditions (i.e., multimorbidity) is the most common chronic health problem in adults. However, clinical practice guidelines have primarily focused on patients with a single disease, resulting in uncertainty about the care of patients with multimorbidity. The American Thoracic Society convened a workshop with the goal of establishing a strategy to address multimorbidity within clinical practice guidelines. In this Workshop Report, we describe a framework that addresses multimorbidity in each of the key steps of guideline development: topic selection, panel composition, identifying clinical questions, searching for and synthesizing evidence, rating the quality of that evidence, summarizing benefits and harms, formulating recommendations, and rating the strength of the recommendations. For the consideration of multimorbidity in guidelines to be successful and sustainable, the process must be both feasible and pragmatic. It is likely that this will be achieved best by the step-wise addition and refinement of the various components of the framework.