Stroke is a leading cause of functional impairments. The ability to quantify the functional ability of poststroke patients engaged in a rehabilitation program may assist in prediction of their functional outcome. The Functional Independence Measure (FIM) is widely used and accepted as a functional-level assessment tool that evaluates the functional status of patients throughout the rehabilitation process. From February to March 2009, we searched MEDLINE, Ovid, CINAHL, and EBSCO for full-text articles written in English. Article inclusion criteria consisted of civilian and veteran patients posthemorrhagic and ischemic stroke with an average age of 50 years or older who participated in an inpatient rehabilitation program. Articles rated 5 or higher on the PEDro (Physiotherapy Evidence Database) scale were analyzed, including one cluster randomized trial and five cohort studies. Descriptive and psychometric data were outlined for each study. Key findings, clinical usefulness of the FIM, potential biases, and suggestions for further research were summarized. Although limited, evidence exists that FIM scores can be used as an accurate predictor of outcomes in poststroke patients.