Dendrimers containing from 9 to 18 tryptophan residues at the peryphery have been efficiently synthesized and tested against HIV replication. These compounds inhibit an early step of the replicative cycle of HIV, presumably virus entry into its target cell. Our data suggest that HIV inhibition can be achieved by the preferred interaction of the compounds herein described with glycoproteins gp120 and gp41 of the HIV envelope preventing interaction between HIV and the (co)receptors present on the host cells. The results obtained so far indicate that 9 tryptophan residues on the periphery are sufficient for efficient gp120/gp41 binding and anti-HIV activity.