This paper reported the aggregate results and studies of complexes erbium, Ytterbium, Lutetium with L-histidine. Complexes of erbium (Er), ytterbium (Yb), lutexi (Lu) with L-histidine mole ratio 1:3 wasisolated in the solid. By the method of elemental analysis, thermal analysis and infrared spectroscopy have identified complexes is composed of H3[Ln(His)3Cl3]. nH2O (Ln: Er, Yb, Lu
n = 2, 3, 6). Each L-histidine molecules associated with Ln3+ through nitrogen atom of the amino group -COO. The complex is unstable and complex thermal dissociation.