Captive breeding, also known as captive propagation, is a conservation strategy aimed at preserving endangered or threatened species by breeding them in controlled environments, such as wildlife reserves, zoos, botanic gardens, and other conservation facilities. It is sometimes employed to help species that are being threatened by the effects of human activities such as climate change, habitat loss, fragmentation, overhunting or fishing, pollution, predation, disease, and parasitism.

For many species, relatively little is known about the conditions needed for successful breeding. Information about a species' reproductive biology may be critical to the success of a captive breeding program. In some cases a captive breeding program can save a species from extinction, but for success, breeders must consider many factors—including genetic, ecological, behavioral, and ethical issues. Most successful attempts involve the cooperation and coordination of many institutions. The efforts put into captive breeding can aid in education about conservation because species in captivity are closer to the public than their wild conspecifics. These accomplishments from the continued breeding of species for generations in captivity is also aided by extensive research efforts ex-situ and in-situ.

Captive breeding techniques began with the first human domestication of animals such as goats, and plants like wheat, at least 10,000 years ago. These practices were expanded with the rise of the first zoos, which started as royal menageries such as the one at Hierakonpolis, capital in the Predynastic Period of Egypt.

The first actual captive breeding programs were only started in the 1960s. These programs, such as the Arabian Oryx breeding program from the Phoenix Zoo in 1962, were aimed at the reintroduction of these species into the wild. These programs expanded under The Endangered Species Act of 1973 of the Nixon Administration which focused on protecting endangered species and their habitats to preserve biodiversity. Since then, research and conservation have been housed in zoos, such as the Institute for Conservation Research at the San Diego Zoo founded in 1975 and expanded in 2009, which have contributed to the successful conservation efforts of species such as the Hawaiian Crow.

The breeding of species of conservation concern is coordinated by cooperative breeding programs containing international studbooks and coordinators, who evaluate the roles of individual animals and institutions from a global or regional perspective. These studbooks contain information on birth date, gender, location, and lineage (if known), which helps determine survival and reproduction rates, number of founders of the population, and inbreeding coefficients. A species coordinator reviews the information in studbooks and determines a breeding strategy that would produce most advantageous offspring.

If two compatible animals are found at different zoos, the animals may be transported for mating, but this is stressful, which could in turn make mating less likely. However, this is still a popular breeding method among European zoological organizations. Artificial fertilization (by shipping semen) is another option, but male animals can experience stress during semen collection, and the same goes for females during the artificial insemination procedure. Furthermore, this approach yields lower-quality semen, because shipping requires extending the life of the sperm for the transit time.

There are regional programmes for the conservation of endangered species:

The objective of many captive populations is to hold similar levels of genetic diversity to what is found in wild populations. As captive populations are usually small and maintained in artificial environments, genetics factors such as adaptation, inbreeding and loss of diversity can be a major concern.