Background: Endoscopic procedures are performed for diagnosis and treatment of GI disturbances and require adequate, short-time anesthesia. Propofol is a rather recently introduced IV drug used for its conscious sedation effects. This study has compared the effects and complications of propofol versus midazolam in endoscopic procedures in Hamedan in 2001. Materials and Methods: This double blind randomized clinical trial was performed on 70 patients at ASA class I- II who underwent endoscopy or colonoscopy at Ekbatan Hospital in Hamedan. After randomization of the patients into 2 study groups: test (propofol) and control (midazolam), phentanil (5mg/kg) was administered as a sedative and after 3 minutes contents of syringe A (propofol) or B (midazolam) were injected by an anesthesiologist. Then, the 2 groups were compared regarding such points as injection pain, conscious sedation, operation satisfaction (by the patient), duration of recovery, nausea and vomiting, hypotension and decrease in O2 saturation. Results: Average score of conscious sedation in midazolam group (4.1) was slightly higher than propofol group (4). Mean duration of recovery was 15.3 in midazolam and 14.8 in propofol groups. A total of 14 patients (40%) in midazolam group and 7 patients (20%) in propofol group experienced complications whose difference was not statistically significant. Mean pain score in midazolam group (2.7) was slightly higher than propofol group (2.6). Mean satisfaction score was also slightly higher in midazolam group (3.23) vs propofol group (3.2). Conclusion: There was no statistically significant difference between propofol and midazolam from the point of view of conscious sedation, patient satisfaction, duration of recovery, injection pain and other complications.