Inductively coupled plasma mass spectrometry (ICP-MS) is reviewed as an alternative nuclear analytical technique for the determination of radioisotopes. The latest development and utilization of collision and reaction cells in ICPMS is presented. These cells are used to promote reactive and non-reactive collisions with resultant benefits in interference reduction, isobar separation, and thermalization/focusing of ions in ICP-MS. Novel ion–molecule chemistry schemes, using a variety of reaction gas reagents selected on the basis of thermodynamic and kinetic principles and data, are now designed and empirically evaluated with relative ease, and a significant body of ICPMS applications now exists in the literature. Results for separations of isobaric overlaps via cation reactions with NO, N2O, O2, CO2, C2H2, and CH3F in an inductively coupled plasma collision/reaction cell mass spectrometer (ICP-CRC-MS) are reviewed.