We explore the potential of using a quartz crystal microbalance based technique for the characterization of living cells during the process of adhesion to a surface. The combined information from simultaneously recorded changes in resonant frequency and energy dissipation is used to extract qualitative information about the cell adhesion process. Adhesion of small colonies of less than 100 cells in a serum-free environment can readily be detected and characterized. The evolution of the dissipation factor in combination with resonant frequency provides a fingerprint of the cell adhesion process, which is sensitive to properties of the surface as well as the type of cell.