The naked mole rat (NMR) is a small eusocial rodent. Because of its remarkable longevity (maximal lifespan, 32 y) and resistance to cancer, the NMR has emerged as a valuable model for aging and cancer research. However, breeding NMR can be difficult. Here, we report the successful introduction and acceptance of pups into a foreign colony with existing pups of different ages. Among the 7 NMR colonies in our satellite facility, one had a consistently poor record of pup viability, with nearly 100% preweaning mortality in multiple litters born over the course of 2 y. The queen of this colony gave birth to 18 pups in January 2013; by 2 d after parturition, it was evident that the pups were not receiving sufficient nourishment. To salvage the litter, the most vigorous pups were cross-fostered to another queen that had recently given birth. On postparturition day 1 (PD1), two pups from the poorly nourished donor litter were bathed with warm water, rolled in recipient colony bedding, and transferred to the recipient colony, which included 8 PD14 pups. The new pups were accepted by the recipient queen, who continued to produce milk in response to suckling by the donor pups well past the weaning of her own litter. This case report provides evidence of successful cross-fostering of NMR pups despite age differences between donor pups and those in the recipient litter; this technique may prove beneficial to researchers struggling with NMR breeding issues.