To evaluate hospitalized patients' understanding of their plan of care.Interviews of a cross-sectional sample of hospitalized patients and their physicians were conducted from June 6 through June 26, 2008. Patients were asked whether they knew the name of the physician and nurse responsible for their care and specific questions about 6 aspects of the plan of care for the day (primary diagnosis, planned tests, planned procedures, medication changes, physician services consulted, and the expected length of stay). Physicians were interviewed and asked about the plan of care in the same fashion as for the patients. Two board-certified internists reviewed responses and rated patient-physician agreement on each aspect of the plan of care as none, partial, or complete agreement.Of 250 eligible patients, 241 (96%) agreed to be interviewed. A total of 233 (97%) of 241 physicians completed the interview, although sample sizes vary because of missing data elements. Of 239 patients, 77 (32%) correctly named at least 1 of their hospital physicians, and 143 patients (60%) correctly named their nurses. For each aspect of care, patients and physicians lacked agreement on the plan of care in a large number of instances. Specifically, there was no agreement between patients and physicians on planned tests or procedures for the day in 87 (38%) of 231 [corrected] instances and in 22 (10%) of 231 [corrected] instances. Complete agreement on the anticipated length of stay occurred in only 85 (39%) of 218 instances.A substantial portion of hospitalized patients do not understand their plan of care. Patients' limited understanding of their plan of care may adversely affect their ability to provide informed consent for hospital treatments and to assume their own care after discharge.