We studied the microflora of Quebec sphagnum peat moss samples taken from five different locations in a peat moss processing plant: soil, drying stacks, sedimented dust (walls and floor), and in bagged peat moss. Large numbers of microorganisms were found; the predominant ones were of the genus Monocillium (up to 112 × 106 colonies/g of dry peat) and the genus Penicillium (320 × 104 colonies/g dry weight). These moulds were more abundant in the processed peat moss than in the peat soil (e.g., Monocillium: soil, 138 × 103; processed peat, 112 × 106). Aspergillus spp. were absent in all five sample sites. We conclude that Quebec peat moss contains large quantities of microorganisms and that moulds become more concentrated during the processing of the peat from the soil to the final product.