Toxicity and heavy metal tolerance potentials of hyphomycetous fungi from epipellic sediments of the Qua Iboe Estuary, Nigeria were investigated ex situ in laboratory microcosms. Indigenous fungi were exposed to Pb, Zn, Ni, Cu and Cr for 90 days following sediment simulation with varying concentrations of the appropriate metallic salts. Growth pattern after acclimation revealed that Aspergillus glaucus - $ESM_7$ exhibited tolerance to Cr, A. repens - $ESM_4$ to Zn and A. niger - $ESM_{10}$ to Cu. Fusarium semitectum - $ESM_{18}$ tolerated Ni and Penicillium digitatum-$ESM_8$ resisted toxicity due to Pb. However results of the toxicity assay showed that the radial growth rate of A. glaucus - $ESM_7$ was retarded by $60;mgl^{-1}$ of Cr, while that of A. repens - $ESM_4$ in $328;mgl^{-1}$ of Zn and Penicillium digitatum-ESM8 in $140;mgl^{-1}$ of Pb were apparently enhanced by the metals. On the other hand Ni at $241;mgl^{-1}$ was toxic and highly inhibitory to F. semitectum - $ESM_{18}$ while $83;mgl^{-1}$ of Cu significantly (Students t-test, P = 0.05) enhanced the growth of A. niger - $ESM_{10}$ when compared with the control. Based on these findings A. niger may be regarded as a promising mycoremediation agent for the removal of Cu from metal contaminated environment. It is also suggestive that because of the growth enhancing effect of Zn and Pb on A. repens - $ESM_4$ and Penicillium digitatum - $ESM_8$ minimal concentrations of the metals may plausibly be incorporated into mycological media for quick recovery of the moulds. On the other hand because of its toxic effect on Fusarium semitectum - $ESM_{18}$, Ni may be adapted as an excellent biocide component for the formulation of fungicidal preparations against plant diseases caused by fusaria provided that the acceptable background level of Ni is not exceeded. However, more detailed information is required in order to optimize the conditions for maximum utilization of these metals and hyphomycetous fungi in useful environmental and biotechnological activities.