Most analytical techniques routinely used for determination of some essential elements (P, S, K, Ca, Mg, B, Mn, Cu, Zn, Co, Mo, Fe and Cl) in plants require destruction of organic matrix of the sample before measurement. A handful of decomposition methods are available for mineralization of plant materials before determination of these elements. Dry ashing and wet decomposition in both classic and modern versions are still most frequent and therefore are described and discussed in this paper. The dry ashing method requires a detailed time temperature standard operation procedure which leads to sufficiently precise and accurate results. Under the controlled conditions, dry and wet decomposition techniques are comparable in their performance. Recently, modern, automated laboratory equipment for both decomposition techniques was developed and introduced to the market. The choice of suitable decomposition methods depends on financial possibilities, and experience of laboratory staff of particular analytical laboratories as well as on traditions and usage of these laboratories. However, the analytical measurement technique should be the dominant factor in this context.