Brown bears (Ursus arctos) in the Cantabrian Mountains of northwestern Spain occur in 2 small, isolated, and endangered populations: the western population (WP) and the smaller eastern population (EP) were studied from 1989 to 2004. We documented the number of unique females with cubs-of-the-year (F_CUB), the number of cubs per female, and the area occupied by F_CUB. The estimated number of F_CUB using the Chao mark–resight estimator was similar to a conservative number of F_CUB obtained using protocols to distinguish unique animals (N̂_Obs). In the WP, N̂_Obs increased during the period, whereas the trend suggested by the index in the EP did not differ from 1.0. The number of cubs per female was slightly higher in the WP (1.8) than in the EP (1.5). The area occupied by F_CUB initially decreased followed by a recovery in both populations. Nevertheless, the area occupied as of 1989–92 had not been completely re-colonized by 2001–04. The areas apparently abandoned by F_CUB were situated in the middle of the 2 populations, so the gap between them was wider in 2001–04 than in 1989–92. We conclude that brown bears in the Cantabrian Mountains are recovering, but the isolation of the 2 populations jeopardizes this recovery. Both populations are still endangered, especially the EP, for which we estimated only 0–3 breeding females/year. Conservation priorities include promoting recovery of range previously occupied by breeding females and increasing contact between the populations.