Rabbi Tendler was ordained at RIETS in 1949 and earned a PhD in biology from Columbia University in 1957. Since 1969 he has served on the Medical Ethics Task Force of the Federation of Jewish Philanthropies, for which he edited Medical Ethics and Halakhah. For six years he served as its chairman. He is also chairman of the Bioethical Commission of the Rabbinical Council of America. He has been a member of the board of directors of Americans for Medical Progress, Inc. He is a member of the following ethics commissions: Society of Critical Care Medicine; Neonatology Ethics Commission, Beth Israel Hospital, New York City; the Good Samaritan Hospital in Suffern, NY; and the National Association of Bioethical Research in Reproduction, originally founded by the American College of Obstetrics/Gynecology and now the leading ethics think tank in the field of reproduction technology.

From 1970 to 1974 Rabbi Tendler was president and then chairman of the board of the Association of Orthodox Jewish Scientists. From 1965 to 1995 he was a member of the Kashruth Advisory Board of the New York State Department of Agriculture. The author of Pardes Rimonim (a text on Jewish family life); Practical Medical Halakhah; Care of the Critically Ill-Responsa of Rav Moshe Feinstein; as well as many articles on science and religion in leading publications, he is frequently consulted by the media and public officials on ethical issues. Moshe Tendler lives with his wife (n?e Sifra Feinstein, daughter of the renowned halakhist Rabbi Moshe Feinstein of blessed memory) in Monsey, New York, where he serves as rabbi of its Community Synagogue. They have eight children.