Advances in medical and science technologies have been prolonging the human life expectancy. But much more effort is needed in diagnosis and treatment of illnesses like cancer. Current methods for treating cancer often destroy both unhealthy and healthy cells. So, it is important to distinguish unhealthy cells from healthy cells for accurate diagnosis and treatment. Nanomaterials, such as nanowires, are promising for labeling cells so that unhealthy cells can be identified and/or selected for specific therapy delivery. In this work, we have developed magnetic nanowire labels that can be used to identify a variety of cell types using ferromagnetic resonance (FMR) which can be engineered to produce unique signatures for each type of nanowire label. Ni, Fe, and Co nanowires were made by template-directed electrodeposition and characterized with vibrating sample magnetometer and scanning electron microscope for magnetic and physical properties, respectively. The nanowire samples were then placed onto a coplanar waveguide for application of a fixed microwave frequency while sweeping a DC magnetic field. Three different trends of FMR absorption vs. applied field were successfully measured for Ni, Fe, and Co nanowires. When measuring mixtures of nanowires with this technique, distinct absorption peaks were evident. In addition, this technique is shown to have the potential for nanowires coated with cell-specific antibodies that can be successfully utilized to tag cells in drug delivery, hyperthermia, or cellular barcoding and manipulation.