In order to examine whether it would be possible to obtain, by a simple extraction procedure from EDTA-erythrocyte-membranes, a partially purified preparation of the "band 3 zone" proteins, we have tested four solubilizing agents of common use. Detergents, both ionic (DOC and SDS) and non ionic (Tween 80 and Triton X-100), were not able, in our experimental conditions, to completely solubilize erythrocyte fragmented membranes which had previously been washed in EDTA-buffers. However, they were able to solubilize some of the membrane proteins, which could then be separated by SDS-PGE. The PGE densitometric profiles reported in this communication indicate that the protein mixture extracted by the ionic detergents DOC and SDS qualitatively reflects the protein composition of the membranes. Among the non ionic detergents, on the other hand, Triton X-100 appeared to be able to extract mainly one band (most probably the band 3 zone), while Tween 80 did not apparently extract any of the membrane proteins. Detergent concentrations, medium composition and experimental procedures are described in detail.