Purpose The aim of this study was to determine if there was a difference between medium term survival outcomes (up to 5 years postoperatively) for patients who had positive surgical margins versus those who had negative margins after undergoing curative resection for early non small cell lung cancer (NSCLC). Methodology Data was obtained from a prospective thoracic surgery database for all patients who underwent curative NSCLC surgery at Sir Charles Gairdner Hospital (SCGH) between January 2009 and September 2019. Demographic data including age, gender, type of surgical procedure performed, histology (surgical margins and visceral pleural invasion) and pathological TNM staging was obtained from the hospital clinical patient management system. The follow-up period was 5 years post surgery. Patients with preoperative staging of greater than IIIA were excluded from the study. Kaplan-Meier and log rank survival analysis were used to compare survival outcomes between patients who had positive margins and those who had negative margins. Results During the study period, 475 patients underwent lung resection at SCGH for preoperative early stage NSCLC (stage I- IIIA). 261 patients (55%) were male, with 372 patients (78.4%) greater than 60 years of age. The predominant postoperative histology was adenocarcinoma (305 patients; 64.2%), followed by squamous cell carcinoma (127 patients, 26.7%). 33 patients (6.9%) had positive surgical margins and 149 patients (31.4%) had some degree of visceral pleural invasion (P1-3). There was a statistically significant difference in survival from 1 year to 5 year postoperatively between those with negative margins and those with positive margins. Conclusion Patients with positive surgical margins after curative surgery for NSCLC had a survival disadvantage up to five years postoperatively compared to patients who had negative margins.