The Mechanical Contractors Association of Metropolitan Washington is a membership organization of contractors who build and service plumbing, heating, ventilation, air conditioning and refrigeration systems in Washington, DC and its Virginia and Maryland suburbs. MCAMW is affiliated with the Mechanical Contractors Association of America.

In common usage, a mechanical contractor can be a company or an individual. If someone asks, "Who was the mechanical contractor on that job?" the answer may be the name of the company that built and installed the plumbing, heating, ventilation, air conditioning and refrigeration; in any building, these are called the "mechanical systems." On the other hand, if the owner, president or any general officer of that company is asked what he does for a living, he would properly respond, "I am a mechanical contractor." Many mechanical contractors both build and service mechanical systems, although some do only one or the other.