In the study, group B streptococci (GBS) isolated from bovines and humans in and around Van, eastern Turkey, were serotyped, and their haemagglutination and lectin-agglutination properties were also determined. This study is the first epidemiological survey of GBS serotypes performed in Turkey. A total of 148 GBS isolates, 76 from bovine milk and 72 from women attending a maternity polyclinic, were examined by co-agglutination, slide haemagglutination and slide lectin-agglutination tests. By the co-agglutination test, 34 (44·7 %) of bovine isolates and 49 (68 %) of human isolates could be serotyped. In bovine isolates, type VII (11·8 %), III (10·5 %), Ic (6·5 %) and VIII (3·9 %) were the most frequently detected serotypes. The most frequent human serotypes were Ic (33·3 %), IV (8·3 %), VIII (6·9 %), V (5·5 %) and R (5·5 %). In the haemagglutination test using rabbit erythrocytes, 23 (33·3 %) bovine and 15 (23·4 %) human isolates were found to be positive. The bovine GBS isolates showed a significant positive agglutination reaction with Dolichos biflorus lectin (30·4 %), whereas the human GBS isolates were found to be positive for Arachis hypogea (18·8 %) and Canavalia ensiformis (37·5 %) lectins. The treatment of GBS with trypsin was also found to be important for the demonstration of the haemagglutination and lectin-agglutination properties of GBS. The results of the study provide data on serotype distribution and the formulation of a possible GBS vaccine in Turkey, and the lectin-agglutination tests may also be useful for differentiating bovine and human GBS strains.