Streptomyces clavuligerus cells were immobilized with two different supports - via sponge and 4% alginate; and cephamycin C production in repeated batch operations were estimated and compared. A gradual increase was observed in cephamycin C production from 48 to 96 h during fermentation. Sponge immobilized cells showed better production levels than alginate immobilized cells. Even in terms of operational considerations such as ease of preparation of immobilized cells, ease for repeated operations when compared, sponge was a better support material than alginate for immobilization.