OBJECTIVE: To determine how the reliability of frequency-volume charts (FVCs) vary with their duration when used to assess patients with lower urinary tract symptoms (LUTS) and whether the duration influences patient compliance. METHODS: Peer-reviewed studies involving patients with LUTS were searched systematically, with the selected studies assessed for their internal and external validity and statistical quality. Details of the patients and type of FVC used were summarized, and reliability coefficients and levels of compliance were extracted for commonly assessed FVC variables. RESULTS: In all, 13 studies were considered to meet the review criteria; they assessed the reliability of FVCs lasting 1, 2, 3 and 7 days. The reliability coefficients for 3- and 7-day FVCs were generally >0.8; those for shorter charts tended to be lower, but strong conclusions could not be drawn due to study limitations. There was no obvious relationship between the duration of the FVC and the level of compliance. CONCLUSIONS: Strong recommendations cannot be made about what duration of an FVC should be used to assess or monitor patients with LUTS. The current consensus on using FVCs of > or = 3 days seems to be the most defensible policy, but more research of high quality is required, especially into the relationship of FVC duration with compliance.