We compared readings obtained from the Baxter-Edwards continuous jugular bulb venous oximetry catheter with those obtained from blood gas analysis of simultaneously drawn samples from the catheter in 12 patients undergoing neurosurgical procedures. Within the range studied (SjvO2, 42-95%), the 111 (median, nine samples per patient; range five to 17) oximetric catheter readings correlated well with hemoglobin oxygen saturation values obtained from in vitro analysis of simultaneously drawn blood samples from the catheter (y = 0.93x + 3.4, r = 0.94, p < 0.001). Fiberoptic light signal was suboptimal (signal quality index = 3 or 4) on fewer than five occasions per patient during an average surgical procedure duration of seven h, and these occurrences were generally corrected by flushing the catheter. We conclude that the Baxter-Edwards jugular bulb oximetric catheter provides an accurate measure of SjvO2 during neurosurgical procedures.