Objective: To introduce a brief quantitative measure of cognitive orientation (to place, time, and situation) developed for daily use at bedside with rehabilitation inpatients. The Orientation Log (O-Log) is a 10- item scale that allows for partial credit based on responsiveness to logical, multiple-choice, or phonemic cueing. It is formatted for rapid visual analysis of orientation trends that can be used to evaluate pharmacologic and cognitive-behavioral interventions. Design: Descriptive study of the O-Log's reliability (interrater and internal consistency). Setting: Inpatient rehabilitation center affiliated with a large university medical school. Patients: Fifteen neurorehabilitation inpatients. Results: For individual items, Spearman rho interrater reliability coefficients ranged from .851 to 1.00. The interrater reliability of the total score was .993. O-Log internal consistency (coefficient alpha) was .922. Conclusions: The O-Log is a reliable and easily administered scale that promises to be a useful tool in monitoring cognitive recovery during rehabilitation.