Four methods often used in preparing leaves for studies on the fate of leaves falling into mid-latitude streams were analyzed in a tropical rainforest stream. Both t h e techniques and plant species affected processing rates for four species of tropical wet forest riparian plants. More leaf area remained for fresh leaf disks than for dried leaf disks. Photometric rather than the usual dry leaf mass measurement techniques were used because, 1) leaves do not have to be dried before they are used, 2) artificially dried leaves do not simulate natural conditions, especially in humid tropical forests, 3) leaves can be measured photometrically and replaced in streams without damaging tissue, 4)photometric methods are commonly used in terrestrial studies on leaf damage and these methods should be equally adaptable to aquatic systems, and 5) the correlation between leaf area loss and dry mass loss for terrestrial studies has been shown to be high; therefore, dry mass data from studies on aquatic leaf decomposition studies are expected to be similar to photometrically-derived leaf area data.