Surveys of physicians' attitudes regarding the therapeutic value of marijuana are rare. Drawing on a national sample of family physicians, general internists, obstetrician-gynecologists, psychiatrists, and addiction specialists, 960 (adjusted response rate 66%) offered opinions about the legal prescription of marijuana as medical therapy. Thirty-six percent believed prescribed marijuana should be legal and 26% were neutral to the proposition. Non-moralistic attitudes toward substance use were significantly associated with support for physician prescription, as was internal medicine and obstetrics-gynecology specialization. Physicians are, in general, less supportive than the general American public regarding the use of medical marijuana.