Phanerochaete chrysosporium strain ME446 produced laccase when grown in a medium with high nitrogen (24 mM), glucose, acetate buffer and high copper (0.4 mM CuSO4). Copper appeared to serve as an inducer. The highest amount of laccase activity was found in 2–3 day old cultures. Both intracellular and extracellular laccases eluted as four peaks (L1–L4) on a MonoQ (anion exchange) column. All four peaks from intracellular fluid appear to comprise multiple polypeptides that gave rise to a ∼400 kDa peak on a gel filtration column. Extracellular laccases had a non-denaturing Mr of 100 kDa.