Background: The release of CD30 molecule in the soluble form (sCD30) is considered a feature of Th2 activation and proliferation of the cellular phenotype Th2. Aim: To analyze the immunoregulatory role of sCD30 in the evolution of hepatitis B virus (HBV) infection. Patients and methods: Three study groups were formed: 15 patients with acute infection by HBV who remitted toward the resolution of the infection; 15 patients who evolved to the carrier state and 15 subjects without clinical history of infection by this or other viruses. The determination of serological markers for the HBV was done by the Microparticles Enzymatic Immunoanalysis techniques (MEIA). The method of double antibody by ELISA was used For sCD30 determination. Results: A significant sCD30 increase (p < 0.05) was observed in patients with acute infection, during the acute phase (135.7 ± 36.7). These values decreased to 16.2 ± 2.5 during the convalescent phase. Patients that evolved to the carrier state, did not experience a rise in sCD30 values (40.2 ± 6.7, 38 ± 9.2 and 36.1 ± 8.3 during the acute phase, at 120 and 240 days respectively). The value in the control group was 34.8 ± 6.7. Conclusions: The group that evolved towards remission experienced a higher activation of the Th2 cellular phenotype, promoting humoral immune response. An inactivity of sCD30 values was observed in the group that evolved to the carrier state (Rev Méd Chile 2001; 129: 1248-52).