Abstract Aims Age, sex, and cardiovascular disease have been linked to thromboembolic complications and poorer outcomes in COVID-19. We hypothesize that CHADS2 and CHA2DS2-VASc scores may predict thromboembolic events and mortality in COVID-19. Methods and results COVID-19 hospitalized patients with confirmed SARS-CoV-2 infection from 1 March to 20 April 2020 who completed at least 1-month follow-up or died were studied. CHADS2 and CHA2DS2-VASc scores were calculated. Given the worse prognosis of male patients in COVID-19, a modified CHA2DS2-VASc score (CHA2DS2-VASc-M) in which 1 point was given to male instead of female was also calculated. The associations of these scores with laboratory results, thromboembolic events, and death were analysed. A total of 3042 patients (mean age 62.3 ± 20.3 years, 54.9% male) were studied and 115 (3.8%) and 626 (20.6%) presented a definite thromboembolic event or died, respectively, during the study period [median follow 59 (50–66) days]. Higher score values were associated with more marked abnormalities of inflammatory and cardiac biomarkers. Mortality was significantly higher with increasing scores for CHADS2, CHA2DS2-VASc, and CHA2DS2-VASc-M (P < 0.001 for trend). The CHA2DS2-VASc-M showed the best predictive value for mortality [area under the receiver operating characteristic curve (AUC) 0.820, P < 0.001 for comparisons]. All scores had poor predictive value for thromboembolic events (AUC 0.497, 0.490, and 0.541, respectively). Conclusion The CHADS2, CHA2DS2-VASc, and CHA2DS2-VASc-M scores are significantly associated with all-cause mortality but not with thromboembolism in COVID-19 patients. They are simple scoring systems in everyday use that may facilitate initial ‘quick’ prognostic stratification in COVID-19.