Description: We have validated a noninvasive computerized tail-cuff system for measuring blood pressure in mice. The system was designed to perform all functions automatically, including a programmable routine of cuff inflation and deflation, analysis and assignment of pulse rate and blood pressure, and recording of data electronically. These data show that blood pressures measured on trained mice by a computerized noninvasive tail-cuff system are reproducible and correlate well with intra-arterial blood pressures measured on unrestrained, unanesthetized mice.