The aim of the present study was to investigate the therapeutic efficacy of immunotherapy after microwave ablation (MWA), which was used to improve liver function, reduce the recurrence rate and enhance survival period in patients with hepatocellular carcinoma (HCC). Between February 2009 and December 2010, 14 patients received immunotherapy after MWA (immunotherapy group) and 15 patients received MWA alone with no post-ablated adjuvant therapy (control group). Immune and liver parameters, recurrence rate and survival time were recorded. The absolute lymphocyte count in the immunotherapy group exceeded that in the control group after 3 courses of immunotherapy (P<0.05). No significant differences were detected in the lymphocyte subset distribution in the control and immunotherapy patients prior to ablation (P>0.05); however, certain cytotoxic subsets (CD3(+)/CD8(+), CD8(+)CD28(+) and CD3(+)CD16(+)CD56(+) T cells) were over-represented and negative regulatory or helper subsets (CD4(+)CD8(+), CD4(+), CD4(+)CD25(+)) were under-represented in the immunotherapy group between 1 and 12 months after immunotherapy (P<0.05). After 2 courses of immunotherapy the proliferation rate of myeloid dendritic cells and T lymphocytes, including CD3(+)/CD8(+) lymphocytes, significantly increased (P<0.05 and P<0.01, respectively). In addition, the level of albumin in the immunotherapy group exceeded that in the control group after 3 courses of immunotherapy (P<0.05). However, the rate of disease-free survival and overall survival within 16 months of MWA did not differ significantly between the two groups (P>0.05). In conclusion, the results of the present study indicate that immunotherapy improves the immune status and liver function of patients with HCC.