Three decadal birth cohorts (1837-1846), 1870-1879 and 1900-1909) each of approximately 500 individuals, were constructed retrospectively through the parish records of the Moravian Mission at Mamre in the Western Cape region of South Africa. Nominative data collection techniques were used to determine the infant mortality rates (IMR), quinquennial mortality rates (QMR) and life expectancies of the three cohorts. The quality of the data was investigated, specifically non-registration and attrition. Overall, male registration coverage was substantially better than that for females. Birth registration was best for the 1837-1846 cohort for males and females, with the 1900-1909 registration being next best. Infant death registration was most complete for males in these two cohorts, but was poor for females. Based on these data, the IMR for the cohorts bom in 1837-1846, 1870-1879 and 1900-1909 (196, 182 and 128 per 1000 respectively for males and 160, 172 and 97 per 1000 respectively for females) appeared to be underestimates. There was some evidence of a downward trend for the IMR with time for males, but this was not statistically significant. For the three cohorts QMR did not differ statistically for males, but for females the third cohort was consistently lower than the other cohorts. The difference was small (well within the 95% confidence interval) but the third cohort ranked consistently below the other two. The life expectancies did not differ significantly between cohorts. The life expectancies at birth (range 34-40 years for males and 32-45 years for females) were probably overestimates due to biased IMR. The life expectancies at age 1 (range 41-44 for males and 37-49 for females) were considered to be more representative figures. Life expectancies at age 20 (37-45 years) were fairly stable over time except for females in the 1900-1909 cohort whose life expectancies were substantially higher than the figures for the earlier cohorts. All mortality indices investigated in this study consistently showed a lighter burden of mortality in historical Mamre compared to 'coloureds' in the Cape Colony at the turn of the century. This is probably the result of the better housing, environmental, social, economic and educational conditions on the missions relative to the rest of the Colony in the century after the emancipation of slaves.