What is Dr. House’s primary medical specialty in House M.D.?

Dr. House’s primary medical specialty in House M.D. is diagnostic medicine.

House leads the hospital’s Department of Diagnostic Medicine, a team created to investigate patients whose illnesses have resisted ordinary diagnosis. The department’s cases often involve multiple organ systems, rare diseases, or misleading symptoms.

The show also establishes that House is board-certified in both infectious disease and nephrology. Those qualifications explain his deep knowledge of infections, kidney disorders, toxins, and systemic illness, but they are distinct from his role as the hospital’s diagnostician.

A common mix-up is to answer nephrology or infectious disease because those are House’s formal specialties. The canonical department associated with his job in the series is Diagnostic Medicine, which functions as the story’s central investigative unit.