The processes of biodeterioration on mural paintings have often been discussed, whereas the causes of contamination have seldom been examined. Many microorganisms responsible for the biodeterioration of paintings are of airborne origin. It follows that an investigation on the aerial microbial concentration and air movements in painted indoors is very useful. This paper reviews the literature of mural painting biodeterioration and the aerobiological studies of painted indoors. Hypogean environments, for their particular microclimatic conditions, are not considered. The fungal species most frequently found in the biodeterioration of wall-paintings are reported, as well as comparisons of surface contamination and aerobiological investigation. This review shows the necessity of finding the best sampling methodologies for cultural heritage studies. The control of airborne contamination and proper sampling methods are highly important in determining treatment strategies for the conservation and prevention of microbial attack on painted surfaces. © 1993 The Italian Association of Aerobiology.