Experiments were designed to determine the role of heme and the importance of other factors in the growth of Campylobacter pylori. Campylobacter pylori strains were tested for their ability to synthesize porphyrin, for their ability to grow and be maintained on basal medium and basal medium supplemented with blood or blood products, and for the influence of bovine serum albumin and catalase on viability. Results indicated that Campylobacter pylori does not require heme as a source of porphyrin. Growth of Campylobacter pylori could not be sustained on media containing starch or hemoglobin, but was sustained on media containing erythrocytes, serum, bovine serum albumin or catalase. The ability to grow on media containing bovine serum albumin and catalase suggests that protection from toxic fatty acids and the prevention of toxic product formation may be important factors in the growth and survival of Campylobacter pylori in vitro. Both bovine serum albumin and catalase combined provide the minimum requirements which allow the spectrum of Campylobacter pylori present in a single culture to grow on blood-free media.