IN ORDER to maximize the biosorption efficiency, eighteen …...experiments were designed to investigate the potentialities of fungal biomass as a resistant and cost effective Cr+6 biosorbent. The influences of individual parameters as well as the interaction between them were studied using Taguchi statistical design. A group of statistical analysis that can define the relationships between the responses of independent variables were carried out. In the current study, it was detected that the biosorbed Cr+6 by A. niger and S. silvatica varied greatly among the 18 media used indicating the importance of optimization experiments in bioprocesses. In case of A. niger the ANOVA analysis of variance revealed that temperature, mycelium status, NaNO3 and agitation were the most significant factors influencing the Cr+6 biosorption .In S. silvatica, temperature, mycelium status, agitation and MgSO4 7H2O were the highly significant variables influencing Cr+6 biosorption .The design detected that the experimental values of biosorbed Cr+6 were in reasonable agreement with the predicted values and the model was significant. The optimized predicted medium from the software design for Cr+6 biosorption by A. niger and S. silvatica was (A) dead mycelium (B) sucrose (15 gl-1) (C) NaNO3 (1.5 gl-1) (D) MgSO4 7H2O (0.1 gl-1) (E)temperature (18 ºC) (F) pH (5) (G) cultivation (static)(H) incubation period (5days).