The baroreceptor, a stretch-sensitive neuron, senses static and dynamic arterial blood pressure and responds by producing a frequency-modulated train of action potentials. The size and anatomy of baroreceptor nerve endings precludes direct experimental study of the details of baroreceptor behavior; however, studies of output firing frequency in response to arterial pressure changes reveal a highly nonlinear input-output characteristic. While many models of the baroreceptor have been developed, most of these models have failed to provide a comprehensive view of the mechanisms under-lying baroreceptor function. We present a new baroreceptor model which provides a physiologically-based, comprehensive description of all aspects of the system. This model combines a mechanical model of the arterial wall with Hodgkin-Huxley-type models of the transducer and encoder sections of the neuron. The complete model not only mimics a wide range of experimental results, it also provides a means of making predictions about baroreceptor behavior and of examining the mechanisms underlying baroreceptor function.