Aim: To evaluate whole cell protein profiling vis-a-vis genotyping to discern phylogenetic relationships among strains of Y. enterocolitica biovar 1A. Methods and Results: Whole cell protein profiling of Y. enterocolitica biovar 1A strains was performed using SDS-PAGE. Twenty-one distinct protein profile types were obtained among a collection of 81 strains isolated from clinical and nonclinical sources. Whole cell protein profiling exhibited discriminatory index (DI) of 0 center dot 80 and clustered the strains into two distinct clonal groups. The clinical and the aquatic serotype O:6,30-6,31 strains were clustered into two discrete subgroups. Conclusions: Whole cell protein profiling displayed sufficient diversity among strains of Y. enterocolitica biovar 1A, and the phylogenetic relationships obtained were in good agreement with those established earlier by genotyping techniques. Significance and impact of the study: Whole cell protein profiling was as discriminatory as some of the genotyping methods and has the potentiality to be used as an adjunct tool to study epidemiology of Y. enterocolitica.