This work describes the evaluation of a wearable plastic optical fiber (POF) sensor for monitoring seated spinal posture, and the development of a workstation interface for the posture monitoring system. A garment-integrated POF sensor was developed and tested on nine healthy subjects. Data from the wearable sensor were compared to data taken simultaneously from a marker-based motion capture system. Peak analysis of the resulting data show a mean value error of 0.64 degrees and a mean time error of 0.53 seconds. These results show that the wearable sensor approximates the accuracy of expert visual analysis, and provides enough accuracy of measurement to reliably monitor seated spinal posture. The initial development of the system hardware and software interface are also described.