Background: Postoperative complications continue to constitute a major issue for both the healthcare system and the individual patient and are associated with inferior outcomes and higher healthcare costs. The objective of this study was to evaluate the trends of postoperative complication rates over a 7-year period. Methods: The NSQIP datasets from 2012 to 2018 were used to assess 30-day complication incidence rates including mortality rate following surgical procedures within ten surgical subspecialties. Multivariable logistic regression was used to associate complication rates with dataset year, while adjusting for relevant confounders. Results: A total of 5,880,829 patients undergoing major surgery were included. Particularly the incidence rates of four complications were found to be decreasing: superficial SSI (1.9 to 1.3%), deep SSI (0.6 to 0.4%), urinary tract infection (1.6 to 1.2%) and patient unplanned return to the operating room (3.1 to 2.7%). Incidence rate for organ/space SSI exhibited an increase (1.1 to 1.5%). When adjusted, regression analyses indicated decreased odds ratios (OR) through the study period years for particularly deep SSI OR 0.92 [0.92–0.93], superficial SSI OR 0.94 [0.94–0.94] and acute renal failure OR 0.96 [0.95–0.96] as the predictor variable (study year) increased (p < 0.01). However, OR’s for organ/space SSI 1.05 [1.05–1.06], myocardial infarction 1.01 [1.01–1.02] and sepsis 1.01 [1.01–1.02] increased slightly over time (all p < 0.01). Conclusions: Incidence rates for the complications exhibited a stable trend over the study period, with minor in or decreases observed.