The effect on long-term survival of immunomodulation adjuvant to various cytotoxic chemotherapy regimens in non-small cell lung cancer (NSCLC) was evaluated in 669 patients followed up between 1974 and 1987. Four hundred seventeen patients were treated only by cytotoxic chemotherapy and served as controls. Two hundred fifty-two patients received warfarin (W), levamisole (L) and tranexamic acid (T) for adjuvant immunomodulation. These drugs, especially when given in combination (W + L + T), led to a significant (p less than 0.05) enhancement of survival in patients with advanced NSCLC, independent of the cytotoxic regimen used.