Multiplexing was used to increase the efficiency of microsatellite analysis in Eucalyptus grandis. Primers were chosen based on the range of eucalyptus SSR alleles and their hybridization temperatures. Choice of PCR conditions proved to be the most important factor; concentrations of primers must be adjusted for use in combination. Results show that 7 primers can be analyzed in 2 PCR reactions, one containing 3 and the other containing 4 primers. Multiplexing promises to be a particularly efficient tool for microsatellite diversity analysis in Eucalyptus grandis.