The size of an enclosure is an integral part of how well it accommodates a nonhuman animal's welfare; however, most enrichment studies concentrate on modifying the area inside the enclosure rather than enlarging it. It has been suggested that rats have little need for more cage space, but there is no empirical evidence about rats' need for space. This experiment provides preliminary evidence for the preferences of 5 male and 5 female albino rats using T-maze choices followed by 5 min dwelling times. The rats showed a moderate but significant preference for the larger of 2 cages (540 cm2 vs. 1,620 cm2binomial z, p <.05). When the rats shared the chosen cage with 4 familiar cage mates, their preference for the larger cage did not become any stronger (paired t(9) = -.820, p > .05). The results suggest that rats should be given a somewhat larger space allowance but could share it with up to 4 other rats.