Aims. The prognostic value of epidermal growth factor receptor (EGFR) mutations in the context of serum carcinoembryonic antigen levels remains controversial in T1 lung adenocarcinoma. Methods. Clinical and pathological characteristics, preoperational carcinoembryonic antigen levels, EGFR mutations, and disease-free and overall survival were analysed retrospectively in 573 pathological T1 patients in East China. Results. EGFR mutations were detected in 220 of 573 patients (38.4%). Patients with serum carcinoembryonic antigen levels ≥ 2.12 ng/mL had worse disease-free (P<0.001) and overall survival (P<0.001) than had others, although survival was comparable between patients with and without EGFR mutations. However, patients with exon 21 mutations in EGFR had significantly better overall survival than had patients with exon 19 mutations (P=0.016), although disease-free survival was comparable (P=0.424). Among patients with serum carcinoembryonic antigen levels ≥ 2.12 ng/mL, disease-free (P=0.019) and overall survival (P<0.001) was also better than that in those with exon 21 mutations. Finally, the exon 19 deletion was found to be an independent predictor of unfavourable overall survival (P=0.037). Conclusions. EGFR mutations were associated with preoperational serum carcinoembryonic antigen levels ≥ 2.12 ng/mL. In patients with levels above this threshold, those with the exon 19 deletion have less favourable prognosis than have those with the exon 21 mutation.