Alpacas and llamas are induced ovulators. They show marked reproductive seasonality in the Andean region, but under Northern Hemisphere conditions of feeding and management, they are non-seasonal breeders. Puberty is attained when they reach 50% of adult body weight. When they are not exposed to a male, females show successive waves of follicular maturation and atresia. Growth, maintenance and regression of a follicle each require an average of 4 and 6 days in alpacas and llamas, respectively. After sterile mating, progesterone concentrations in blood were increased from day 5, reached maximum concentrations on day 7-8, and declined rapidly at 9-10 days after mating. A fertile mating results in formation of a corpus luteum that remains functional throughout gestation. The duration of gestation is 340-346 days. Almost all fetuses were found to occupy the left uterine horn, even though ovulation occurs from both ovaries with equal frequency. Several methods of pregnancy diagnosis have been described. Mating is recommended within 15-20 days after parturition to obtain good fertility rates and one offspring per year. The factors that contribute to high rates of embryonic mortality are unknown. Reproductive technologies, such as AI, superovulation, embryo transfer and IVF, have not been used very extensively in these species but can be successfully applied.