Background: Measurement of liver volume has been used in planning radiotherapy dosimetry, assessing the progressiveness of various diseases and measuring the response to treatment. Objective: To measure liver volume using multidetector computed tomography (MDCT), and to evaluate the accuracy and inter-observer reliability of liver volume measurement using MDCT. Methods: Measurements were done using a track-ball to draw its outline manually, and calculate by summation of each slice volume which was measured in 8 mm thickness. The calculated liver volume was compared to the actual liver volume which was measured by water replacement. Results and conclusion: There was a strong correlation between the calculated and actual liver volumes performed by a radiologist and a technician (98.0 % and 97.1 % agreement, respectively). High observer reliability was identified (99.2 % agreement). This technique can be easily used by well-trained personnel such as radiologists or technicians.