Aims: To investigate the use of quartz crystal resonant sensor (QCRS) technology to determine the adhesion of Staphylococcus epidermidis to fibronectin-coated surfaces. Methods and Results: QCRS sensors (14 MHz) with 4 mm gold electrodes were coated with fibronectin and exposed for 15 min to suspensions of Staph. epidermidis ranging in concentration from 1 × 102 to 1 × 106 cfu ml-1. Changes in resonant frequency were recorded and showed a linear relationship with the logarithm of cell concentration over the range tested. Conclusions: QCRS technology was shown to be a rapid, sensitive and non-destructive method for measuring the adhesion of bacteria to surfaces. Significance and Impact of the Study: This report demonstrates that QCRS technology has the potential to be used for a range of applications requiring measurement of bacteria on surfaces. In particular, it may be used for the real-time monitoring of bacterial biofilm formation.