The authors performed a retrospective descriptive and analytical cohort study of prehospital patient initial refusal of care (PIRC) cases to characterize the types of patients encountered and to assess factors associated with their dispositions. During a 6-month period, 169 of 1715 (9.9%) base station calls in an urban emergency medical service (EMS) system were for physician involvement in a PIRC. Patients' dispositions were as follows: left at scene against medical advice (53%); taken by ambulance to the hospital (28%); left with friend (13%); other disposition (5%). While police were called to the scene 41 times, they placed a "legal hold" on only 10 patients. Leaving the patient at the scene against medical advice was associated (logistic regression analysis; P less than .05) with the absence of the following factors: family on the scene and a police hold, and with the presence of the following factors: treated hypoglycemia, alcohol use, orientation, and normal speech. The development of statutes that allow police hold placement under the guidance of the base station physician may be necessary. Such statutes would aid transportation of a patient considered by EMS personnel to have impaired mental capacity that may limit the patient's ability to understand medical care decisions.