The decomposition and nutrient release from Eucalyptus deglupta and Coffea arabica leaf litter and Erythrina poeppigiana green leaves, alone or mixed, was studied on two coffee farms in Southern Costa Rica. E. deglupta litter had the slowest decomposition rates (k = -0.08 and -0.16), while the decomposition of E. poeppigiana litter was fastest (k = -0.58; evaluated only in one farm). The presence of green E. poeppigiana leaves increased the rates of decomposition and release of P from C. arabica litter and of K from E. deglupta litter. The concentrations of N, P, K and homocellulose were positively correlated to decomposition rates, whereas polyphenol and the lignin: N ratio were negatively correlated.