The effect of gallic acid, vanillic acid, and molasses spent wash (MSW) concentration on growth and decolourizing capability of four fungi (Geotrichum candidum, Coriolus versicolor; Phanerochaete chrysosporium and Mycelia sterilia) was studied. Fungal growth was inhibited to a varying extent in the presence of gallic and vanillic acid, except for G. candidum, which was unaffected by gallic acid. G. candidum and P. chrysosporium growth rates increased in the presence of increasing concentrations of MSW (up to 50% v/v), however, growth of M. sterilia and C. versicolor was inhibited at spent wash concentrations above 5% (v/v). Increasing the concentration of MSW from 6.25% (v/v) to 12.5% (v/v) increased the decolourizing ability of each fungus, except for M. sterilia. C. versicolor exhibited greatest colour removal with a reduction of 0.43 units at A(475) (equivalent to 53% colour reduction) after 10 days growth in 12.5%(v/v) MSW.