Fungi and substrates undergoing fungal decomposition were collected from forests in northern and southernSweden and analyzed for chlorinated dimethoxybenzenes (DMBs). Specimens were fungi fruiting bodies, rottingwood, forest litter and underlying humus. Targeted compounds were DAME (1,2,4,5-tetrachloro-3,6-DMB) andrelated fungal secondary metabolites. A screening procedure was developed which involved soaking the speci-mens in ethyl acetate followed by analysis by capillary gas chromatography – mass spectrometry with mass selec-tive detection (GC-MSD). DAME was the most frequently found (62% of 47 specimens) and often the most abun-dant target compound, with range and mean ± SD concentrations of <0.0017–3.81 and 0.21 ± 0.63 mg kg−1ww. Based on log-log correlations of partition coefficients of hydrophobic compounds between fungal biomass/water (KD) and octanol/water (KOW), five species of fungi are suggested to produce DAME de novo versus bioaccu-mulation from forest runoff water. Full-scan mass spectra of some high-concentration specimens indicated thepresence of a Cl2DMB and a Cl3DMB, which could not be identified further due to lack of standards, anddrosophilin A (DA = 2,3,5,6-tetrachloro-4-methoxyphenol), the precursor to DAME. Tetrachloroveratrole(TeCV = 1,2,3,4-tetrachloro-5,6-DMB) was found in only a few specimens. This study supports our hypothesis offungi as a source of DAME in terrestrial runoff and indicates that other chlorinated secondary metabolites arepresent. DAME is widely distributed globally, and it would be good to have a better understanding of its sourcesand pathways as a marker of terrestrial organochlorines and their availability for bioaccumulation