A study of the growth of reindeer (Rangifer tarandus) was carried out during the spring and summer of 1958 in the Mackenzie Delta, N.W.T. Growth rates were obtained for four fawns over this period. Their growth is described by Brody's equation and the von Bertalanffy equation. The rate of growth of reindeer fawns is slightly less than that of the Columbian Black-tailed Deer, whereas the birth weight of the reindeer is double that of the Black-tailed Deer. A description of the relative growth of several body measurements is given. Hind foot length, heart girth, height-at-withers, muzzle circumference, and antler length were measured. The measurement error of height-at-withers and muzzle circumference limits the usefulness of this data. The changes in herd numbers and composition of the Mackenzie Delta Reindeer Herd over the period 1938-1958 are analyzed. Of the three population determining factors (natality, mortality, and dispersal), dispersal (losses by straying) was by far most important and natality (number of fawns) was least important in determining the total annual increment to the herd over the period 1938-1958. The age distribution of the herd over the period 1938-1958 has been relatively stable. / Science, Faculty of / Zoology, Department of / Graduate