The authors tested the resistance of pigments to molds appearing in tempera paintings. The number of pigments tested was 31, including five organic ones. Cultures of six sorts of fungi were carried out on mixtures of egg yolk containing a drop of vinegar and each of 31 pigments, on gesso grounds for tempera paintings prepared by various techniques, and on synthetic culture grounds containing agar-agar, dextrose from potato, water and each of the pigments, controlling the temperature, humidity and experiment duration. The results show that most of the pigments, which include all of the five organic pigments, are only slightly resistant to mold growth, although some inorganic pigments, consisting of selenium, lead, iron and cobalt have considerable resistance. CdSe is more effective than CdS. It is very interesting that the resistance of HgS, a harmful substance for the human body, is considered to be lower than that of other pigments. The authors advise painters using tempera techniques to avoid the use of hygroscopic materials and to take the fungal resistance of pigments into consideration.