The objective of this study was to establish a fine woolled Merino flock at the Grootfontein Agricultural Development Institute in order to evaluate the production and reproduction performance of fine woolled animals against a control line on natural pastures in the Karoo. Data collected from 1989 to 1999 were used to evaluate the production and reproduction performance of these two lines. It is evident from the results of this study that the control lambs had a slightly better growth rate than the fine woolled lambs. However, body weight and reproduction of the adult ewes did not differ. The fine woolled animals produced significantly less wool compared to the control line. It can therefore be concluded that it would be possible to produce finer wool effectively under natural pastures in the Karoo.