Background and objective With the popularization of high-resolution computed tomography (HRCT), there is a rising trend of the detection of multiple primary lung cancers (MPLC). Adenocarcinomas is the major pathological type of MPLC. At present, reports on MPLC are relatively common, but few study focused on synchronous multiple primary lung adenocarcinomas (SMPLA). We carried out this study in an attempt to enhance our understanding about SMPLA.Meth-ods Data from 38 patients undergoing surgery for SMPLA in our institution frrom December 2012 and July 2016 were retro-spectively collected.Results Among the 38 patients, 12 patients were male, 26 patients were female, with a median age of 58 (ranging from 39 to 73). Surgical outcomes verified 29 patients with 2 tumors and 9 patients with more than 2 tumors. There were 26 patients with tumors in ipsilateral lung while 12 patients in contralateral lung. Eight patients underwent one-stage surgical treatment for contralateral tumors with mean postoperative hospitalization of 10 days. The gene detection results of 5 patients showed different epidermal growth factor receptor (EGFR) mutations can be found in one patient's different tumors. The 1-year and 3-year overall survival (OS) rate were 96.6% and 74.2%. Larger maximal tumor dimension (P<0.001), advanced pT stage (P=0.003), lymph nodes metastases positive (P=0.001), advanced TNM stage (P=0.022) and postoperative adjuvant chemoradiotherapy (P=0.009) were correlated with poor OS.Conclusion Multiple lung malignant lesions should not be taken as metastasis for granted and the possibility of MPLC also should be considered. Mutational status ofEGFR could be used as a clinical reference to diagnose patients with SMPLA.