Morphological and immunohistochemical studies carried out particularly around the level of the basal ganglia (BG) in birds, are reported and commented on. Our results showed, on paraffin embedded avian BG, both the histological features and the immunohistochemical findings on immunofluorescence distribution of some neuropeptides (especially Metenkephalin) in the striatal complex. By comparing our results of Metenkephalin immunoreactivity (Menkir) with the referred analogous ones of Substance P (SP) quoted in literature, we confirmed the strikingly similar labelling at the levels of the Lobus paraolfactorius (LPO) and Paleostriatum augmentatum (PA), in contrast with the very low immunoreactivity at the Paleostriatum primitivum (PP) levels. We were able also to demonstrate the strong MEnk-ir of the neurons of the Nucleus accumbens, Nucleus septalis and paraventricularis. All these findings are also in accord to the interpretation by many AA (Wynne and Gunturkun, 1995; Reinez et al., 1983), about the anatomical correspondence between the LPO-PA complex of birds and the caudate-putamen in mammals. Some MEnk + 'wooly like fibres' described in our specimens in the PA (on the contrary reported in the Gpe segment of mammals) apparently escape these correspondence.