In this study, an improved method was validated for the determination of some metallic contaminants (arsenic (As), chromium (Cr), cadmium (Cd), lead (Pb), iron (Fe), nickel (Ni), copper (Cu), Mn, and antimony (Sb)) in energy drinks using inductive coupled plasma mass spectrometry (ICP-MS). The validation procedure was applied for the evaluation of linearity, repeatability, recovery, limit of detection, and quantification. In addition, to verify the trueness of the method, it was participated in an interlaboratory proficiency test for heavy metals in soft drink organized by the LGC (Laboratory of the Government Chemist) Standard. Validated method was used to monitor for the determination of metallic contaminants in commercial energy drink samples. Concentrations of As, Cr, Cd, Pb, Fe, Ni, Cu, Mn, and Sb in the samples were found in the ranges of 0.76-6.73, 13.25-100.96, 0.16-2.11, 9.33-28.96, 334.77-937.12, 35.98-303.97, 23.67-60.48, 5.45489.93, and 0.01-0.42 mu g L-1, respectively. The results were compared with the provisional guideline or parametric values of the elements for drinking waters set by the WHO (World Health Organization) and EC (European Commission). As, Cd, Cu, and Sb did not exceed the WHO and EC provisional guideline or parametric values. However, the other elements (Cr, Pb, Fe, Ni, and Mn) were found to be higher than their relevant limits at various levels.