The traditional method of performing trypan blue cell viability analysis involves manual staining and use of a hemocytometer for counting (1). Recent advances in instrumentation have led to a number of semi- or fully automated systems that can increase the throughput and accuracy of this technique. The Beckman Coulter Vi-CELL™ XR Cell Viability Analyzer (2) will be described here, but there are numerous other instruments available, including the Nexcelom Bioscience Cellometer Visionฎ (3), the Invitrogen Countess™ Automated Cell Counter (4), and the Roche Innovatis Cedex (5). In the case of the Vi-CELL™, cell viability can be calculated and reported in percentage, concentration, and cell count, and additional parameters, such as cell diameter and circularity, are also provided. This instrument has been validated against manual cell counting and shown to be highly effective (6).