An integrated optic pressure sensor based on intermodal interferometry is described. The sensor consists of a straight waveguide supporting the lowest-order TM-like and TE-like modes and a rectangular diaphragm as a pressure sensitive region. The waveguide is placed along an edge of the diaphragm to maximize the sensitivity of the sensor. The output intensity of the sensor system is dependent on a difference of phase retardations induced in the two guided modes by the applied pressure via the photoelastic effect. The sensor was fabricated using two glass substrates: a Coming 0211 glass with a thickness of 300 mu m and a thick substrate with a 10mm x 10mm square hole to define the diaphragm. The two substrates were finally bonded together by UV curing adhesion after the waveguide was formed on the thin substrate. The fabricated sensor was tested using a He-Ne laser at 633nm. We successfully obtained the sinusoidal change of the output power versus the applied pressure. The halfwave pressure was evaluated to be about 80kPa experimentally.