Angiotensin II levels in COVID-19 are controversial. We studied 12 hospitalized patients, including their baseline levels of peripheral lymphocyte subsets (via flow cytometry) and plasma angiotensin II (via radioimmunoassay). Controls comprised radioimmunoassay’s 124 healthy subjects. Angiotensin II levels (pg/ml) were elevated among patients versus controls (Mean ± standard deviation: 98.8 ± 146.9 versus 23.7 ± 15.6, p < 0.0001; Median, interquartile range: 27, 20 to 116 versus 22, 14 to 28). Half the patients had lymphocytopenia (< 1000 cells/mm³), and the CD3+/CD4+ counts were negatively associated with body mass index, viral load, hospital stay and non-home discharge. Angiotensin II imbalance appears to be a biomarker for COVID-19 morbidity and merits further investigation.