Although new chemotherapeutic drugs have been applied constantly, their efficacy for non-small cell lung cancer (NSCLC) is still not satisfactory. In recent years, epidemiological investigations have shown that lung cancer may be induced by chronic Chlamydia pneumoniae (Cpn) infection, since stable high titers of Cpn antibodies, especially IgA, are a hallmark of chronic infections. Azithromycin is commonly used for the treatment of Cpn infections; however, there are only few reports regarding the application of azithromycin (A) combined with paclitaxel and cisplatin (TP) for advanced NSCLC. Considering that patients with NSCLC have a higher rate of Cpn infection, we proposed to employ azithromycin for Cpn infection in chemotherapy for advanced NSCLC. The aim of this study was to explore the effects of azithromycin on chemotherapy for NSCLC. A total of 86 patients with stage III-IV NSCLC were randomly divided into TP and ATP groups; the characteristics of patients in the two groups showed no significant differences. The TP group was treated with paclitaxel and cisplatin, and the ATP group was treated with azithromycin combined with TP for at least 4 weeks, followed by evaluation and comparison of efficacy, side effects and patients’ quality of life before and after chemotherapy between the two groups. Testing for Cpn infection revealed a significant difference in the case number before and after therapy in the ATP group (P < 0.01) compared with the TP group (P > 0.05), and a statistical difference was observed (P < 0.01) between the ATP and TP groups after treatment. The changes in quality of life of patients after two different chemotherapy regimens were statistically significant (P < 0.05), but there was a significant difference in only cognitive function after treatment. The changes in symptom scores of patients after the two different chemotherapy regimens were statistically significant (P < 0.05), but there was a significant difference in only shortness of breath and cough after treatment. Kaplan-Meier estimate was utilized to describe the survival function of patients in the two groups. The median survival time was 12.0 months for the TP group and 13.0 months for the ATP group. One-year survival rates of the TP and ATP groups were 45.0 and 75.0%, respectively, which were significantly different (P < 0.05). Our study of azithromycin+paclitaxe l+cisplatin on stage III-IV NSCLC patients achieved favorable results in terms of side effects and overall survival.