Background and Aim: Knowledge of long-term consequences of severe COVID-19 pneumonitis is of outmost importance. Our aim was, therefore, to assess the long-term impact on quality of life and lung function in adults hospitalized with severe COVID-19. Methods: All patients hospitalized with COVID-19 pneumonitis at Copenhagen University Hospital-Hvidovre, Denmark, were invited to participate in the study 4–5 months after discharge. Of the 160 invited 128 responded positively (80%). Medical history and symptoms were assessed, and patients rated impact on quality of life and functional status with EuroQol-5D-5L and Post Covid Functional Scale. Lung function was assessed by dynamic spirometry and measurement of diffusing capacity. Results: Fatigue, dyspnea, cough and cognitive dysfunction were the most common symptoms. Of 128 patients, 85% had at least one symptom, and 51% reported two or more symptoms. Self-rated Quality of life was impaired assessed by EuroQol 5D-5L, with dimensions ‘Pain or discomfort’ (61%) and ‘Usual activities’ (54%) mostly affected. Functional status was significantly worse than before COVID-19 assessed by Post-COVID Functional Scale. Among lung function parameters, diffusing capacity was most affected, with 45% having diffusing capacity < 80% of predicted. Conclusion: Fatigue, respiratory symptoms and cognitive symptoms are highly common months after hospitalization for severe COVID-19. Compared to pre-COVID-19, functional status and usual activities continued to be impaired. In line with this, almost half of the patients were found to have impaired diffusing capacity.