Cultural heritage consists of goods made from almost all types of materials existing in nature, which have been processed resulting in several types of artifacts from very simple mono-components to complex structures that integrate inorganic and organic materials. These cultural heritage goods, even if they are made of stone or metals, are influenced by environmental parameters, which can change their structure and composition. Moreover, because they are inserted into the biosphere they can be degraded by biological mechanisms. The biotransformation process is favored in hot-humid climate areas, where environmental conditions are extremely favorable for the growth of most organisms. An important role is also played by the bioreceptivity of the support material which contributes to the establishment, anchoring and development of biodeteriorants. The role of conservatives is to try to avoid the involvement of environmental factors and restorers to repair the damage suffered. The process of growth and vegetative development of organisms has a direct consequence on the conservation of cultural assets by inducing changes in both their compositional and structural characteristics. The species that degrade these materials range from microscopic bacterial cells to higher plants and animals. The main types of biodegradation derive from the metabolic activity of organisms / microorganisms leading to physical, chemical and aesthetic degradation, while their intensity is strictly correlated with: the type and size of the organism involved; the type of material and its state of preservation; environmental conditions, microclimatic exposure; the level and types of air pollutants. Various methods have been used to classify and quantify the microorganisms and macroorganisms involved in biodegradation processes. Ecological and physiological parameters related to the development of specific biodeteriogens were investigated together with the effect of their increase on material weather. In direct or indirect conservation interventions, methodologies have been applied to stop or slow down the biodeterioration process. Methodologies and products should be chosen taking into account the type of substrate and the species to be treated in situ so as not to cause negative interference with the materials and to have a low impact on the environment.