Lower jaws and measurements were obtained from 473 mountain reedbuck Redunca fulvorufula culled on two reserves in the north-eastern karoo of South Africa. All mandibles were allocated to subjective age classes that were based on tooth-eruption and tooth-wear. In a sample of 69 jaws. the molar and premolar cementum annuli were counted by examining bisected whole teeth under reflected light. One light line appeared to have been deposited per year, and a usable relationship between tooth-wear category and cementum line count was obtained. although indistinct and paired lines often confused the picture. Good correlations were also obtained between the number of cementum lines and the crown height of the first molar (r2= 0.68) and the second molar (r2= 0.77). Actual ages of immatures were estimated by comparing peaks in the distribution in the different age classes with the age since expected mean birth date in different culls. The age of transition to adult dentition (pL 30 months) was determined from two females that were earmarked when young and shot two years later. Von Bertalanffy (1957) growth curves were fitted to measurements of body mass, jaw length and horn length in males to aid field identification of immatures. Asymptotic body mass was reached at 30 months in females and 40 months in males, and asymptotic jaw length was reached at 30 months in both sexes. Horns in males only reached full length at about five years.