Hydrogen solubility in molten aluminium at different temperatures from 973-1123 K, has been measured using Sieverts’ method. Inert gas (helium or argon) was used as a reference gas to calibrate the measurement system of the Sieverts’ apparatus. The measured hydrogen solubility was found to vary with the reference gases. Helium was detected to be soluble in liquid aluminium. When helium is used as the reference gas, its solubility resulted in lower measured hydrogen solubility than that when argon was used to calibrate the measurement system of the apparatus. Argon gas was therefore considered as an appropriate reference gas when Sieverts’ method is used to measure the hydrogen solubility in liquid aluminium. The hydrogen solubility, S, in liquid aluminium as a function of melt temperature, T, determined in the present investigation is expressed as log S = (-2980/T) + 3.07.