Reported are results of 200 centrifuge runs of 24 monkeys Macaca mulatta. Microgravity effects were simulated by 4-wk immobilization with the head tilted down at -6 degrees. The investigation was divided into two series. During series-1, one group of animals was not exposed to centrifugal training, whereas the other group was exposed to +Gz at the magnitudes of 1.2, 1.4 and 1.6 G for 30-40 min 4 to 5 times a week. In series-2, again one group of animals was not trained on the centrifuge but the other was trained at +1.2 Gz for 30 min 2 or 3 times a week. Functional testing by 30-s runs at +3 Gz was performed before and after head-down immobilization. Deterioration of g-load tolerance following simulated microgravity in both groups of untrained macaques was ascribed to the deconditioning effect of simulated microgravity on the body systems. Centrifugal training had, as a rule, positive effect on g-tolerance of the animals though it failed to fully eliminate the negative consequences of simulated microgravity. This means that search after optimal protocols of application of artificial gravity generated by centrifuge needs to be continued. Evaluation of the effectiveness of combining centrifugation with other countermeasures against the adverse effects of microgravity and development of associated protocols can be another area of future research.