OBJECTIVES: The present study aimed to clarify the association between preoperative biopsy and surgical outcomes in clinical stage I non-small-cell lung cancer (NSCLC) with different proportions of ground-glass opacity (GGO). METHODS: Data on patients who underwent pulmonary resection for NSCLC from 2006 to 2016 were drawn from a prospective registered database and analysed retrospectively. Patient characteristics collected included tumour size, location and staging, surgical approach, consolidation-tumour ratio, histopathology and the presence or absence of preoperative biopsy to identify the independent prognostic factors of disease-free survival (DFS) and cancer-specific survival. A 1:1 propensity score matching was conducted between the preoperative biopsy and reference groups based on their baseline characteristics measured before the decision for preoperative biopsy. RESULTS: A total of 1427 patients were collected to achieve an overall 5-year DFS as 84.5% (median follow-up: 67.3 months), stratified to be 99.5% in the GGO-dominant group (n = 430) and 78.2% in the solid-dominant group (n = 997). Only 2 patients (0.5%) in the GGO-dominant group experienced tumour recurrence. For solid-dominant tumours matched with propensity scores (279 in preoperative biopsy vs 279 in reference group), the independent predictors of DFS included preoperative biopsy, sublobar resection, pathological staging and angiolymphatic invasion. Preoperative biopsy was a predictor of cancer-specific survival in univariable analysis but was not in multivariable analysis. Significant differences were also found between matched groups in those with late-delay surgery, but not in patients receiving preoperative biopsy with early-delay surgery (≤21 days). CONCLUSION: Preoperative biopsy may worsen surgical outcomes in patients with clinical stage I, solid-dominant NSCLC.