One hundred and fifty-nine caribou (Rangifer tarandus caribou) were collected from the area of precalving distribution of the George River population in northern Labrador between April 3 and 15, 1980. The sample revealed that caribou of northern Labrador reach physical and reproductive maturity earlier than most other free-ranging caribou populations in North America. Females attained mature values for lean body weight and shoulder height by 34 months and for total body length, heart girth, and mandible length by 46 months. Pregnancy rates for females 22, 34, and 46 months and older were 43, 90, and 95%, respectively. Measurements of fat reserves showed George River females to be in superior physical condition during spring migration than caribou on mainland Northwest Territories. Fat reserves, however, were substantially less than comparable values for females collected from the same population in March, 1976. The calf: pregnant female ratio was 42:100, suggesting a 1st year rate of mortality of approximately 58%. The most common internal parasites were Cysticercus tenuicollis and Fascioloides magna. It is concluded that the recent growth of the George River population has resulted from early female physical and reproductive maturity, low adult mortality, and high survival of calves.