A noteworthy collection of drawings (c. 1885-1930) produced by Louis Comfort Tiffany (1848-1933) and his studio artists sustained significant mold damage prior to its acquisition by the Metropolitan Museum of Art in 1967. In order to be exhibited, published, and studied safely, the works required conservation intervention. The works, which were water damaged sometime between 1933 and 1967, were sampled for molds using both classical and molecular techniques to identify the fungi present. The range of molds isolated by culturing were identified using their ITS (internal transcribed spacer) region sequences vie searching for similarity in GenBank. Five species were identified as belonging to: Aspergillus fumigatus, Cladosporium sp., Fusarium oxysporum, Penicillium chrysogenum, and Penicillium sp. In contrast DNA extracted directly from dark, thick-walled spores present on the paintings showed a 98% similarity to Chaetomium sp. When compared with GenBank registries. Similarly from brown stained paintings, fungal samples were amplified. In their ITSI-5.8-ITS2 region 80% of the clones matched Cladosporium with a 99% similarity. Yet, the remaining 20% of the clones matched 100% of the 2 ITS regions of Chaetomium sp. with a 98% similarity. A similar trend occurred with samples of mixed brown fungal spots from another work, where 80% of the clones matched Thielavia hyalocarpa, and the remaining 20% of the clones corresponded to Cladosporium oxysporum. The apparent disparities (80:20) at first sight could represent differences in the proportions of the two molds originally present, but they also may be related to the degradative processes that affect DNA, or to the order of colonization. For instance, Chaetomium sp. could be detected with sequences of a few hundred base pairs while Chadosporium sp. was identified with fragments of more than 500 bp. These overall results may indicate that Chaetomium sp. was an earlier colonizer or that Cladosporium sp., because its DNA was still in better condition, could be thought of as a later colonizer of the drawings. Cladosporium sp., Chaetomium sp. and Thielavia appear as the primary degraditive culprits, while the other general isolates may be thought of as contaminants. Unfortunately, the interpretations cannot be defined in a better manner from the historical background of the collection, since the disposition of Tiffany's drawings was unknown prior to 1967. Based on the analyses of the existing damage, it has been supposed that sometime between 1930 to around 1967 the collection sustained water damage. It is unclear how the handling of these 400 works, during the past decades, may have affected cross-contaminations among the drawings. In overview, the investigations indicate that the molecular techniques give a more definitive picture than do classical techniques of the fungal species composition on a work of art. This has implications in terms of restoration and conservation. In this instance, treatment methods should focus on removal of Chaetomium sp. and Cladosporium sp. or their by-products of metabolism, with lesser attention directed to A. fumigatus, F. oxysporum, P. chrysogenum, and Penicillium sp.