With decreased illegal hunting and better habitat conservation, the Florida Key deer (Odocoileus virginianus clavium) population grew from an estimated 25–50 animals in the late 1940s to approximately 200 animals on Big Pine and No Name keys, Florida, USA, by 1971, the last official survey. U.S. Fish and Wildlife Service (USFWS) trend data indicate that the deer population continued to increase after 1971; however, current deer density estimates are necessary for the proposed reclassification of the Key deer from endangered to threatened. Our study objectives were to (1) obtain current population estimates of Florida Key deer and compare these to historical estimates, (2) evaluate survey methods (USFWS mortality and deer counts) in detecting changes in population trends, and (3) outline a protocol for future monitoring. Road counts (n = 889) were conducted from January 1971 to December 1971 and January 1976 to December 2001 on Big Pine and No Name keys. From mark–recapture data, we estimated that the Key deer population on these 2 islands increased by 240% between 1971 and 2001 (2001 estimate: 453–517 deer). Trend data indicated that annual deer mortality was a function of deer density or population size (r_s = 0.743). We compared the annual finite rate of increase (R) from USFWS annual deer counts and mortality data (R = 1.053–1.065) to mark–recapture studies (R = 1.038) and found them to be similar (P = 0.66–0.67). This similarity suggests that all 3 methods (USFWS deer counts and mortality data, and mark–recapture data) can be used to monitor changes in Key deer density.