Öz The effect of a cationic surfactant Dodecyl thrimetyl amonium bromide (DTAB) on Remazol blue dye bisorption properties of living and dead A. versicolor biomass was investigated in this study. The effect of surfactant on biosorption and the functions of pH, dye and surfactant concentration was examined. Dye removal of fungal biomass was 58.1 % in the presence of 0.5 mM DTAB and 31.3 % in the absence of DTAB after incubation for 6 hours. In order to determine the optimal pH value, pH 3 to 7 with 0.5 mM DTAB was examined and the maximum biosorption was occurred as 58.1 % at pH 6 in 100 mg Lsurfactant and dye concentration on bioremoval the surfactant concentration was varied from 0.5 to 2 mM and dye concentrations were 50,100 and 150 mg L-1. Dye uptake by fungal biomass increased with an increase in surfactant concentration. To understand the dye removal activity of only fungus in the presence of DTAB, the dye removal value of only DTAB have been subtracting from the dye removal value of fungus with DTAB. The results showed that cationic surfactant DTAB enhanced dye biosorption by A. versicolor. The removal process used in this study is also a new approach and has a high value to remove reactive dyes from wastewater