In this work, crude oil characterization based on surface plasmon resonance (SPR) is demonstrated. Oil characterization plays a crucial role in both the upstream and downstream oil industry. The application of SPR to these opaque, high index fluids is made possible here using infrared light (lambda = 1550 nm) for which crude oil is largely transparent, coupled through a high-index prism. Bitumen-toluene mixture tests show a measurement sensitivity of 74 degrees RIU-1 and a limit of detection below 1% toluene. Seven crude oils from around the world are differentiated with refractive indices (RIs) spanning 1.44-1,56, with a sensor limit of detection of 0.0006 RIU. These results indicate a significant potential for SPR as a non-intrusive, fast, and simple technique for crude oil characterization applicable to reservoirs, surface facilities, and pipelines.