Background: H1N1 influenza has a high mortality rate due to its potentially life-threatening complications. The current study aims to investigate the relationship between the outcomes of the disease and clinical, paraclinical, and imaging findings in patients with H1N1 influenza. Methods: In this retrospective cross-sectional study carried out at Imam Khomeini Hospital, Iran, medical records of 64 patients hospitalized from 21 March to 21 September 2019 were analyzed. Recorded clinical information and paraclinical and imaging findings of the patients were extracted and compared with the course of their disease. Clinical outcomes were defined as the death or survival of the patients. The data were analyzed using the SPSS software. Results: The mortality rate in the patient was 9.4% (6 patients). 81% had the following concurrent predisposing diseases: hypertension (17.8%), cardiovascular disease (13.7%), and diabetes mellitus (11%). Approximately 80% (51%) had received oseltamivir. In the patients, the most common presentations were cough (13.4%), fever (13.2%), and myalgia (10.8%). In the deceased patients, the oxygen saturation was decreased (P=0.037), and the pulse rate (P=0.012), respiratory rate (P<0.0001), alkaline phosphatase levels (P=0.001), and ALT levels (P=0.003) were increased. In the CT scan reports, in more than 53% of the patients, all lung lobes were involved with ill-defined margins in 94% of the patients, with the most common sites of the lesion being central and peripheral (27%) and posterior (22%) regions. Conclusion: Oxygen saturation, pulse rate, breathing rate, and laboratory findings (ALP and ALT) can predict the prognostic of the patients with H1N1 influenza.