Botrytis cinereais an important plant pathogenic fungi with a wide host range, which can make use of different infection mechanisms. Although genetic variation for resistance to B. cinereahas been observed within some species, no gene-for-gene relationship has been found. The development of resistant genotypes is, therefore, complicated. Any attempt to develop control strategies makes it necessary a detailed knowledge of both the fungal infection mechanisms and the plant defence mechanisms. The application of different experimental approaches allows the analysis of the infection process in different hosts, the description of the elements that participate in each stage of the process and the identification of those pathogenicity factors which are essential for the establishment of the interaction. The characterisation of the latter will provide information about key elements of the infection process as the basis for the development of effective, long term and environmentally friendly control strategis.