The determination of lanthanides by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is complicated by several spectral over laps from M +, MO+ or MOH+ions formed in the ICP. Especially, it is essential to avoid the spectral interferences from lighter lanthanide and Ba polyatomic ions on mid die or heavier lanthanides. To tackle this problem, we have developed a mathematical correction method, which reduces all the spectral over laps from oxide species of Pr, Nd, Ce and Sm over Gd, Tb, Dy and Ho, and Gd, Tb over Yb and Lu. It can also success fully correct the oxide and hydroxide interference of Ba over Eu. The effectiveness of the proposed the mathematical correction scheme is demonstrated for the USGS Standard Rock samples AGV-1 and G-2. The results show that the experimental data obtained by applying the mathematical correction scheme for lanthanides is in good agreement with the reported values, using pneumatic and ultrasonic nebulisation methods, for their ICP-MS analysis.