The SurePath liquid-based Pap test (LPT) is successfully and widely used to assess sputum cytology. This study aimed to compare the cytological findings and diagnostic sensitivity of LPT with those of the conventional Pap smear (CPS) method for diagnosing lung cancer. Bronchial brushing specimens from 204 patients diagnosed with lung cancer were studied. LPT slides showed decreased areas of cell monolayers, a clearer background and distinct, stereoscopic cytological features. The LPT had a significantly higher diagnostic sensitivity for lung cancer (71.6%) than the CPS method (57.8%, p \ 0.05), particularly for small cell lung carcinoma and [2 cm lesions (p \ 0.05). Combination of the LPT with the CPS method showed obviously higher diagnostic sensitivity for the detection of adenocarcinoma (63.6%), central lesions (85.0%) and [2 cm lesions (81.4%) compared with the CPS method alone (p \ 0.05, p \ 0.01). Thus, LPT is a useful and easily performed technique that can be widely applied, and is suitable for the early diagnosis of lung cancer.