Primary biliary cirrhosis is an autoimmune cholestatic liver disease characterized by humoral and cellular response directed at mitochondrial autoantigens, mainly the E2 component of the pyruvate dehydrogenase complex. The etiology of PBC, like most polygenic autoimmune diseases, belongs to the "complex" category, including genetic elements and environmental factors. Many environmental factors, such as xenobiotics, smoking, hormonal therapy, toxins, oxidative stress and recurrent urinary tract infections, are associated with PBC. Infectious agents can trigger autoimmunity via several mechanisms and are associated with various autoimmune diseases. A relationship between PBC and several infectious agents, and a possible role for Escherichia coli in the pathogenesis of PBC, have been suggested. The identification of a culprit agent that induces or exacerbates PBC might have diagnostic and therapeutic implications. This review evaluates the evidence for an infectious agent role in the pathogenesis of PBC.