Importance: A little known on early and late outcomes of abdominal surgery in patients with coronavirus disease 2019 (COVID-19). Objective: To describe early and late complications after abdominal surgery in patients with COVID-19. Design, setting, and participants: A prospective cohort study is conducted at Astghik Medical Center, Yerevan, Armenia, from February 1 until October 31, 2020. The study population comprised 259 patients with COVID-19 and 245 patients without COVID-19 matched by operation type, age, sex, and comorbidities, underwent abdominal surgery. Differences between early (1-30 postoperative days) and late (31-60 postoperative days) complications in both groups were analyzed. Exposures: Patients with COVID-19 had been diagnosed based on both clinical and laboratory (RT-PCR, reverse transcriptase-polymerase chain reaction assay in nasopharyngeal swabs) criteria at least 14 days before abdominal surgery. Patients without COVID-19 were not screened at time of surgery, but were free from any respiratory symptoms and had negative RT-PCR results during preoperative 14 days. Main outcomes and measures: The primary endpoints were early and late postoperative complications. Secondary endpoints were to determine 60-day surgical mortality and the impact of comorbidities as additional risk factor of postoperative complications in patients with COVID-19. Results: A total of 29 patients with COVID-19 developed early or late postoperative complications. Only 4 patients without COVID-19 with early postoperative complications were identified. The median age of patients with COVID-19 who had early and late postoperative complications were 54.5 (range: 45-64) and 69.5 (range: 65-74), correspondingly. At least one comorbidity was present in 25 (86.2%) of 29 patients with COVID-19 who developed early or late postoperative complications. A 60-day surgical mortality was 14.3%. Conclusion and Relevance: COVID-19 is associated with high risk for postoperative complications of abdominal surgery even if surgical procedures are performed after 14 days of COVID-19 onset. Only patients aged 45 to 74 years developed complications in our study. Presence of at least one comorbidity was an additional risk factor of postoperative complications. Larger and better designed studies are needed to find out indicators for early detection of postoperative complications in patients with COVID-19, especially in people older than 45 years and in those with comorbidities.