Kefir is a sour, viscous, slightly carbonated and alcoholic milk beverage, which is traditionally fermented using a culture of bacteria and yeasts. The influence of kefir on health has been well studied in mice and rats. However, research on kefir use in ruminants is rather limited. The aim of this study was to investigate the effect of kefir as a probiotic on the performance of goat kids during the pre- (45 days) and post-weaning (45 days) periods. Forty eight kids were randomly allocated to four treatment groups: Control, Kefir, Auto-Kefir (autoclaved) and Probiotic (a commercial probiotic). The kids were weaned at 45 days of age. The supplementation of different probiotics did not have any significant effect throughout the study on live weight and weight gain of the kids as compared to the Control group. Milk intake or milk-based nutrient intake of kids did not differ significantly among treatments in the pre-weaning period. Similarly, the intake of concentrate feed and nutrients from the concentrate was not affected by the treatments during post-weaning. No significant differences in faecal consistency of kids were found among the treatments. The results of the study indicated that supplementation of kefir as a natural probiotic or a commercial probiotic source does not improve performance of goat kids under the conditions in the present study and suggest that new approaches are required for studying the efficacy of this probiotic.