A new type of pressure sensor, using fiber optic measurement techniques, has been designed and tested for biomedical applications. It has the advantage of being able to avoid kinetic errors when measuring static pressure under flow conditions. The sensor consists of two parts, a diaphragm which converts the pressure into mechanical displacement, and a fiber optic displacement sensor which converts the mechanical displacement into a light intensity change. The fiber optic displacement sensor is composed of two fibers which are polished at their endfaces, aligned and attached to the diaphragm. A theoretical analysis shows that a small displacement generated by the diaphragm is linearly related to the transmitting light intensity loss, and this relationship has been experimentally obtained with a linearity of ±1.796, and a slope of 2.36mV/um. Regression analysis yielded a 0.9983 correlation coefficient. The complete fiber optic pressure sensor has a sensitivity of 2.03mV/mmHg with a linearity of ±1.3%, and the correlation coefficient of 0.9991. The results suggest that this kind of sensor may have very promising applications for catheter based in vivo static pressure measurements.