OBJECTIVE: To describe the diagnosis, symptomatology and disease course of COVID-19 in nursing home (NH) residents in the Netherlands. DESIGN: Prospective cohort study. METHOD: Data on NH residents with suspected COVID-19 were collected from the electronic patient records. Data were collected on diagnostic status (COVID-19: confirmed/excluded (using the RT-PCR test)), symptomatology (typical/atypical and other symptoms, body temperature and oxygen saturation) and, in the case of confirmed COVID-19, on disease course (recovered/clinically improved/deteriorated, deceased). We described and compared the symptomatology in NH residents with confirmed COVID-19 and NH residents in whom COVID-19 had been excluded. We also analysed mortality risk using survival analysis. We used registrations from the period 18 March to15 April 2020 for this study. RESULTS: We reported on 1,969 NH residents with suspected COVID-19. The diagnosis was confirmed in 857 patients (43.5%); diagnosis was excluded in 1,112 (56.5%) patients. Among patients with confirmed COVID-19, 65% had coughs, 70% had fever, 33% had shortness of breath, 28% had delirium/confusion and 10% had a sore throat; in patients in whom COVID-19 was excluded these symptoms were experienced in 70%, 47%, 45%, 26% and 13% of patients, respectively. Of the patients with confirmed COVID-19, 48% died within 30 days (95% CI: 36-44%), versus 20% of the patients in whom COVID-19 was excluded (95% CI: 11-15%). CONCLUSION: There is a lot of overlap in symptomatology between NH residents with COVID-19 and those with other acute diseases. An RT-PCR test is required to be able to make the distinction better. The mortality risk in patients with confirmed COVID-19 is significantly higher than in patients in whom covid-19 is excluded.