•In this real-world analysis of 205 patients with resected stage I-III NSCLC rate for recurrence and secondary primary lung cancer was 22 % and 8 %, respectively.•83 % of recurrences, and 65 % of SPLC were detected on FDG-PET/CT that was done after 6, 12 and 24 months after resection.•In this patient cohort second curatively intended treatment was possible in 37% of pts with recurrence and 100% with SPLC.•Recurrence was identified in more than 80% of all cases in one of the three FDG-PET/CTs during the first two years after resection.•A postoperative surveillance strategy with regular FDG-PET/CT scans is able to identify curatively treatable recurrences with high percentage. The optimal surveillance strategy in patients with resected non-small cell lung cancer (NSCLC) is unknown. Early detection of recurrences by follow-up imaging might improve survival and whole-body 18F-FDG-PET/CT might be the optimal imaging modality given its high accuracy in preoperative staging. Data from a single-center cohort of 205 patients with resected stage I-III NSCLC and FDG-PET/CT surveillance was retrospectively collected. Patients had preoperative FDG-positive tumors and FDG-PET/CT at 6, 12, 24 months, chest CT at 18 months. Thereafter, annual chest CT was performed for stage I-II, annual FDG-PET/CT for stage III. With a median follow-up of 26.3 months (range, 4.1–60.6), the rate for recurrence and secondary primary lung cancer (SPLC) was 22 % and 8 %, respectively. Associated symptoms were present in 48 % (recurrence) and 18 % (SPLC) of patients. Overall, 83 % of recurrences, and 65 % of SPLC were detected on FDG-PET/CT. 82 % of recurrences were detected in one of the first two follow-up PET/CT scans. Second curatively intended treatment (SCIT) was possible in 37 % of patients with recurrence and 100 % with SPLC. The 2-year recurrence-free survival rate after SCIT for recurrence was 53 % 95 %CI; 31–91 %. Non-malignant FDG-positive findings occurred in 25 % of patients (71 % possible infections). In our cohort of patients, more than 80% of all recurrences were identified in one of the three FDG-PET/CTs performed as part of our imaging protocol during the first two years after resection. Nearly all patients with non-distant recurrence qualified for a SCIT. Further studies are needed to identify patients who might benefit from an even more intensive surveillance strategy.