C. jejuni and C. coli isolates from diverse sources in Calcutta were serotyped and biotyped according to the Lior scheme. Of the 55 strains examined, 85.5 per cent reacted with one or another of the 73 antisera available. This included the formation of two new serogroups, LIO 67 and LIO 76. C. coli serogroup LIO 46 biotype II was the most frequently encountered strains (14.5%), followed by C. coli serogroup LIO 29, 55 biotype II (10.5%) and C. jejuni serogroup LIO 54, biotype I (5.5%). Serogroups recovered from animals and birds were also found to be prevalent in strains isolated from clinical sources, confirming the zoonotic implications of the disease.