In the context of monitoring environmental factors, metals are one of the major analytical components. Applying appropriate determination methods and obtaining accurate results is a requirement imposed on environmental laboratories that perform quality control of water, soil, waste or vegetation. This study presents some examples of certified reference materials for quality control of the results of toxic metal determination from solid environmental and vegetation samples. The analyzed and verified metals were As, Cd, Cr, Cu, Ni, Pb and Zn. The pre-treatment of the samples, the determination methods of metals and the obtained results are also presented. Inductively Coupled Plasma Optical Emission Spectrometry (ICP-EOS) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) techniques are suitable for low metal concentrations, while ICP-EOS and Flame Atomic Absorption Spectrometry (FAAS) methods can be used at high concentrations.