Recently, during a rotation as the attending physician on our cardiology consult service, a patient we were seeing for atrial fibrillation with rapid ventricular response was reported to me as being autistic. Thinking about this term and the patient being examined, I realized that I really knew very little about autism, and decided it was time to do some research on this entity. What I discovered was, in fact, quite interesting.1–5 I am writing this commentary because autism is common here in the US, and I believe that it is important for internists to know more about this condition that can affect the care of individuals with other illnesses commonly seen by internal medicine physicians.