The short duration and fast onset of action of alfentanil underpins its suitability for use in anesthetic techniques. In these case studies, we have assessed the efficacy, safety and feasibility of alfentanil as an analgesic adjuvant of propofol based general anesthesia. Propofol was titrated to Keep the bispectral index in the 40 50 range. Alfentanil was infused at the effect site concentration of 80 or 160 ng/ml using a computer assisted continuous infusion. Two patients in this pilot study showed stable hemodynamics, smooth emergence and satisfactory postoperative pain control with additional analgesics in PACU.