The purpose of this prospective, randomized, double blind study was to compare the onset and duration periods of pulpal anesthesia using 2% lidocaine with 1:100,000 epinephrine, 4% articaine with 1:100,000 epinephrine and 4% articaine with 1:200,000 epinephrine in inferior alveolar nerve block (IANB). Thirty subjects received 1.8 mL of each of the three local anesthetic solutions in IANB. Onset and duration periods of pulpal anesthesia were determined using electric pulp stimulation. The mean time of onset of pulpal anesthesia was 8.7, 7.4 and 7.7 min and the mean duration of pulpal anesthesia was 61.8, 106.6 and 88.0 min for 2% lidocaine with 1:100,000 epinephrine, 4% articaine with 1:100,000 epinephrine and 4% articaine with 1:200,000 epinephrine, respectively. For onset, there was only a significant difference between 2% lidocaine with 1:100,000 epinephrine and 4% articaine with 1:100,000 epinephrine (p=0.037). For duration, there was significant difference for all the local anesthetic solutions (p≤0.05). In conclusion, 4% articaine with 1:100,000 epinephrine exhibited faster onset and also had longest duration of pulpal anesthesia in IANB.