The cell morphology is a valuable indicator of the physical condition and general status of the cell. Here we demonstrate a methodology for noninvasive biosensing of adherent living cells. Our method is based on infrared reflection spectroscopy of living cells cultured on thin Au film. To characterize cell morphology we utilized the unique properties of the infrared surface plasmon (λ=1-3 μm) and infrared guided wave that travel inside the cell monolayer. We demonstrate that our method enables monitoring of submicron variations in cell morphology in real-time and in a label-free manner. In addition to morphological characterization, our method allows investigation of chemical composition and molecular structure of cells through infrared absorption spectroscopy analysis.