The occurrence of perylene in the Middle Jurassic fossil wood from Poland is described, along with its correlation with unsubstituted polycyclic aromatic hydrocarbons (PAHs) as well as cellulose content. Perylene is especially common in immature/low maturity organic matter (OM), largely of terrestrial origin (e.g. Louda & Baker 1984, Jiang et al. 2000, Grice et al. 2009). It has been found in diverse recent environments, such as marine and terrestrial sediments, including peats, as well as ancient deposits, including brown coal and hard coal, crude oil and sedimentary rocks (review in Marynowski et al. 2013). Here we link perylene, a product of wood-degrading fungi, to conifer biomarkers in fossil wood material of different ages. Middle Jurassic wood remnants were of relatively low maturity (ca. 0.2-0.4% vitrinite reflectance Rr), had excellent preservation of biomarkers and biomolecules and generally good preservation of anatomical structures due to early diagenetic mineralisation. The results from described (most taxonomically defined) fossil wood fragments demonstrated a negative correlation between the concentration of perylene and those of generally typical conifer biomarkers (e.g. cadalene, dehydroabietane, simonellite and retene). We defined a conifer wood degradation index as: CWDI = perylene / (perylene + cadalene + retene + simonellite + dehydroabietane); and observed a wide range of values (0.001 for less degraded wood to 0.95 for highly degraded samples). We determined similar δ13C values for perylene from the fossil wood samples (from -26.4% to -27.8%), whereas the values for the conifer biomarkers were slightly higher and varied from -25.6% to -26.6%. In contrast, pyrene was depleted in 13C (from -27.5% to -28.2%). The carbon isotope values of perylene are consistent with an origin from wood-degrading fungi.