Aspects of the cryopreservation of piroplasms have been studied. The majority of the experimental work was carried out on 2abesia rodhaini-infected rat blood. The use of three cryoprotectants, glycerol, dimethylsulphoxide tLI+bl) and polyvißylpyrrolidone (AeVx)), was studied. Greatest success was achieved using lll`d6U at a final concentration of 10,o. Three cooling rates, slow, rapid and ultrarapid, were studied. These cooling rates were also measured and are presented in tabular and graphical form. The best results were achieved using the rapid cooling rate. Two containers, glass ampoules and pp60 polythene capillary tubing, were studied, the best results being achieved using pp60. Two methods for the estimation of the degree of damage suffered by babesit , rodhaini-infected rat blood during cryopreservation, percentage haemolysis estimation of host red cells and infectivity measurement, were used. Crystals, thought to be associated with haemoglobin, were often found in frozen and thawed blood samples. it was suggested that these crystals affected percentage haemolysis estimations, rendering this estimation technique invalid, for rat blood. The infectivity results obtained in the penultimate experiment in this study cast some doubt also on the validity of the infectivity titration method used in this study. This is discussed at length in the discussion section of that experiment. stage of infection in the host, level of parasitaemia in the host and nature of diluent used were all shown to have little effect on the ability of babesia rodhaini- infected rat blood to withstand the rigours of cryopreservation. In the last experiment in this study, similar results to those obtained for the cryopreservation of babesia rodhaìni- infected rat blood were obtained for the oryopreservation of Jabesiamicroti- and Fiuttallia musculi- infected mouse bloods. From the results obtained for the three piroplasme studied, and from the evidence in the literature, it is suggested that the best method tested, involving the rapid cooling of DMSO protected blood in pp60 or in glass ampoules could be applicable for the cryopreservation of piroplasms in general.