The study investigates the expression pattern of angiotensin-converting enzyme 2 (ACE2) across over 150 different cell types in human tissues and organs, using stringent immunohistochemical analysis. ACE2 is a key protein involved in the entry of the novel SARS-CoV-2 virus into host cells. The results, compared with mRNA and protein datasets, show that ACE2 is primarily expressed in enterocytes, renal tubules, gallbladder, cardiomyocytes, male reproductive cells, placental trophoblasts, ductal cells, eye, and vasculature. In the respiratory system, ACE2 expression is limited, with no or only low expression in a subset of cells in a few individuals. The study provides a comprehensive resource for understanding SARS-CoV-2 host cell entry and the biology of the disease, aiding in the development of effective treatments.The study investigates the expression pattern of angiotensin-converting enzyme 2 (ACE2) across over 150 different cell types in human tissues and organs, using stringent immunohistochemical analysis. ACE2 is a key protein involved in the entry of the novel SARS-CoV-2 virus into host cells. The results, compared with mRNA and protein datasets, show that ACE2 is primarily expressed in enterocytes, renal tubules, gallbladder, cardiomyocytes, male reproductive cells, placental trophoblasts, ductal cells, eye, and vasculature. In the respiratory system, ACE2 expression is limited, with no or only low expression in a subset of cells in a few individuals. The study provides a comprehensive resource for understanding SARS-CoV-2 host cell entry and the biology of the disease, aiding in the development of effective treatments.