An investigation has been made in order to compare two different intraoral methods for mandibular block analgesia. The first method (according to Fischer) anesthetizes the inferior alveolar and lingual nerves just above the level of the mandibular foramen and the other method (according to Gow-Gates) anesthetizes the mandibular nerve just after leaving the oval foramen. The latter method should, with only one injection, give complete analgesia within the entire distribution zone of the sensory components of the mandibular nerve. The investigation has been performed on 12 test subjects, who each have achieved mandibular block analgesia according to the two methods mentioned above. 1.8 ml lidocaine-adrenaline (20 mg per ml + 12.5 microgram per ml) has been used and the analgesic effect has been tested in the pulps and in the vestibular and lingual mucosa at different time intervals. The investigation shows that the onset of analgesia and complete analgesia was more rapid with the first method than with Gow-Gates' method. Furthermore Gow-Gates' method shows no superiority in anesthetizing the long buccal nerve without separate injection for this nerve. However, regarding the analgesic effect only, there has been no statistically significant difference between the two methods with this small number of test subjects.