Specific antibodies against a whole preparation of glycophorins from rat erythrocyte membrane and against its most prominent component (32 kDa) were prepared. 2. Both antisera and the respective affinity-purified antibodies recognize the 74, 32 and 25 kDa components of rat glycophorins; therefore, a close antigenic relationship between them can be inferred. 3. On the other hand, a cross-reaction with human glycophorin A (both MM- and NN-type) is observed for both antisera. 4. This suggests the existence of epitopes common to human and rat glycophorins.