The purpose of this paper is to illustrate the importance of documentation system for the in situ conservation of Plant Genetic Resources (PGRs). The paper gives information about the international experience in the field of documentation for in situ conservation, and described the most important kinds of information that will increase and make more efficient the process of in situ preservation.The documentation system ReGen developed by Centre for Plant Genetic Resources of Institute of Genetics and Plant Physiology, Academy of Sciences of Moldova regarding in situ conservation consists of six kinds of data: initial data, location – described the condition under which germplasm is collected, sample identity – information concerning the accepted taxonomic name, sampling – consists of information about the maintenance of sample in natural condition, molecular data, gene bank localization – include traditional information for gene bank conservation.