We report a case of baclofen withdrawal syndrome resulting from oral baclofen underdosing. A 24-year-old woman with type 1 neurofibromatosis receiving long-term baclofen therapy was admitted with presumed pneumonia which was successfully treated with antibiotics. The patient continued to have fever and autonomic instability without evidence of infection which entirely resolved within 24 hours of reinstitution of full preadmission dosing of oral baclofen. Baclofen withdrawal syndrome resulting from underdosing of oral baclofen should be considered as a potential source of prolonged fever in the intensive care unit.