The Holy Shroud is a relic of great historical importance that, according to catholic tradition, represents the "Sudarium" i.e. the "Sindon" of Jesus Christ. By several techniques, the most recent studies try to establish a well defined dating of the Holy Shroud. In addition an attempt is also made to find out the best mean to preserve the relic. We have to this purpose performed microbiological tests on specimens (Dusts) from the Holy Shroud establishing the microbic content in various spots. Besides few exceptions, the bacteria and fungi found on the Shroud and related objects are common and spread in all the areas examined.