Abstract The relative contributions of bacteria and fungi to the overall decay of water hyacinth ( Eichhornia crassipes (Mart.) Solms) were determined. Thirteen bacteria and 24 fungi were associated with a situ decaying litter of water hyacinth. Most bacteria were gram-negative, facultative anaerobes, and could degrade polysaccharides and proteins. The fungi were predominantly terrestrial forms. Six fungi grew well on water hyacinth leaves and were actively involved in the degradation of lignocellulose. Remaining fungi grew slowly or failed to grow on water hyacinth leaves. Decomposition experiments have demonstrated that the first 4 days of decay are dominated by non-microbial processes. After 4 days of decay, the contribution of microbial processes increased exponentially and that of non-microbial processes declined exponentially at nearly similar rates. The total loss of ash-free dry matter due to non-microbial processes was about 30% and the remainder was lost due to microbial processes. Bacteria were predominant degraders of the litter, whereas fungi degraded only negligible quantities.