The article reviews the structure, function, and pathophysiological significance of the ecto-nucleoside triphosphate diphosphohydrolase (E-NTPDase/CD39) family of ectonucleotidases. These enzymes, which include NTPDase1, 2, 3, and 8, are located on the cell surface and play crucial roles in modulating extracellular nucleotide concentrations and their effects on P2-receptor signaling. The molecular identification of individual NTPDase subtypes, genetic engineering, mutational analyses, and the generation of subtype-specific antibodies have provided significant insights into their structure and function. These advances have also defined the physiological and pathophysiological implications of NTPDases in various tissues, including the vasculature, nervous tissues, and other organs. The spatial and temporal expression of NTPDases by different cell types impacts a wide range of processes, such as cellular metabolism, adhesion, activation, migration, and developmental responses. Future clinical applications are expected to involve the development of new therapeutic strategies for transplantation and various inflammatory, cardiovascular, gastrointestinal, and neurological diseases.The article reviews the structure, function, and pathophysiological significance of the ecto-nucleoside triphosphate diphosphohydrolase (E-NTPDase/CD39) family of ectonucleotidases. These enzymes, which include NTPDase1, 2, 3, and 8, are located on the cell surface and play crucial roles in modulating extracellular nucleotide concentrations and their effects on P2-receptor signaling. The molecular identification of individual NTPDase subtypes, genetic engineering, mutational analyses, and the generation of subtype-specific antibodies have provided significant insights into their structure and function. These advances have also defined the physiological and pathophysiological implications of NTPDases in various tissues, including the vasculature, nervous tissues, and other organs. The spatial and temporal expression of NTPDases by different cell types impacts a wide range of processes, such as cellular metabolism, adhesion, activation, migration, and developmental responses. Future clinical applications are expected to involve the development of new therapeutic strategies for transplantation and various inflammatory, cardiovascular, gastrointestinal, and neurological diseases.