The white-rot fungus Panus tigrinus CBS 577.79 was cultivated both in mechanical (stirred tank, STR) and pneumatically (bubble column, BCB) agitated bioreactors and investigated for its ability to reduce the polluting load of olive-mill wastewater (OMW). Both aeration and agitation strongly influenced treatment efficiency. Best pollutants biodegradation performances were achieved in the bubble column bioreactor. Using this bioreactor, COD reduction, dephenolization and decoloration were 60.9, 97.2 and 75%, respectively. In contrast, lower depollution efficiency was generally observed in STR due to the possible occurrence of shear stress.