The objective of the study was to develop a method for artificial insemination (AI) in the common marmoset, a New World primate species. For AI to be successful, sperm must be deposited at an appropriate site and time in the female reproductive tract, details of which are currently not available for Callitrichid species. Epididymal sperm were deposited in the cervix of 18 marmoset monkeys (Callithrix jacchus) around the time of expected ovulation using either 3, 2, or 1 inseminations. Six out of 18 females conceived, resulting in the first reported births following AI in this species. These pregnancies show that the presence of coagulum in the vagina and the stimulus of the female reproductive tract by natural mating are not essential for effective sperm transport in this species. Although 3 different timing regimes for sperm deposition relative to ovulation were employed, no protocol was demonstrably better than the others in terms of number of conceptions. The proportions of motile, live, and morphologically normal sperm in the suspensions used for AI were comparable with published values for ejaculates from fertile male macaques. These preliminary results indicate that births are possible following AI in marmosets: the technique could be used to aid effective genetic management of the species and possibly to facilitate captive breeding of endangered Callitrichids. Am.