Importance: Description of the range of clinical-laboratory characteristics of Indian COVD-19 patients. Accurate prediction of requirement for ICU treatment based on routine tests at presentation can advise policy to triage patients into appropriate facilities and save resources.Objective: To study associations of severity of disease and need for ICU treatment in COVID-19 patients.Design: A retrospective study of clinical course in 800 hospitalized COVID-19 patients, and a predictive model of need for ICU treatment.Setting: A dedicated COVID-19 tertiary care hospital in Pune, India (8th April to 15th June 2020).Participants: Eight hundred consecutive patients admitted with confirmed COVID-19 disease.Main outcome: Clinical and laboratory associations of severity of disease, and predictors of need for ICU management.Results: Average age was 41 years, 16% were 2 and abnormal chest X-ray and deranged hematology and biochemistry at admission. A model trained on the first 500 patients, using above variables predicted need for ICU treatment with sensitivity 80%, specificity 88% in subsequent 300 patients; exclusion of expensive laboratory tests did not affect accuracy.Conclusion and relevance: In the early phase of COVID- 19 epidemic, a significant proportion of hospitalized patients were young and asymptomatic. Need for ICU treatment was predicted by simple measures including higher age, symptomatic onset, low SpO2 and abnormal chest X-ray. We propose a cost-effective model for referring patients for treatment at specialized COVID-19 hospitals.Funding Statement: This research study was funded by Symbiosis International (Deemed University), Pune through its internal funds.Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: All patients signed a written informed consent at the time of admission which permitted use of anonymized data for research. The Institutional Research Committee (IRC) of Symbiosis Medical College for Women gave necessary approvals.