Background: Lung ultrasound is an easily available bedside imaging modality that has good specificity for the diagnosis of coronavirus disease-2019 (COVID-19). Limited evidence is available on its utility to predict clinical severity. Materials and methods: In this prospective observational study, adult patients with COVID-19 pneumonia admitted to the intensive care unit (ICU) of a tertiary care hospital between June 2020 and August 2020 were included. Lung ultrasound was performed in at least four areas in each examination and video loops were scored by two independent observers. The statistical relationship was assessed between median lung ultrasound score, chest X-ray score, P/F ratio (ratio of the partial pressure of oxygen in arterial blood to the fraction of inspired oxygen), ROX index, SOFA score, ICU stay, and mortality. Results: Fifty lung ultrasound examinations were performed in 29 patients of age 54.7 ± 15.3 years. P/F ratio was <300 mm Hg during 80% of the examinations. There was moderate correlation between median lung ultrasound score and both ROX index (Spearman's rho = −0.543, p < 0.001) and P/F ratio (rho = −0.522, p < 0.001), while there was weak correlation between chest X-ray score and ROX index (rho = −0.0.345, p = 0.019) and no correlation between chest X-ray score and P/F ratio. There was correlation between chest X-ray score and ICU stay (rho = 0.434, p = 0.049). There was no difference in any of the parameters between survivors and non-survivors. Moderate inter-observer agreement was present between the two observers. Conclusion: Bedside lung ultrasound examination, even with a limited number of views, can reflect the clinical severity of COVID-19 pneumonia.