The complexes of some rare earth elements (Ho
Er) with L-tryptophane have been isolated in solid state. The complexes have the formula [Ln(tryp)3]Cl3..3H20 (Ln: Ho, Er). The structure of the complexes has been recognized by the elemental analysis, IR spectra, thermal analysis methods and electrical conductivity measurements. It was found that the L-tryptophane utilized amino nitrogen and carboxyl oxygen for bonding.