In the spring and early summer of 1953, three cattle herds in south Queensland were dipped in acaricides at intervals such that few or none of the cattle ticks (Boophilus microplus) attacking to the animals between dippings reached maturity. This was continued until the tick larvae hatching in the pastures in spring were greatly depleted in numbers, but was discontinued before they were exterminated, to avert the danger of the cattle losing their immunity to redwater fever. Throughout the rest of the summer and the early autumn these cattle were lightly infested, and required dipping relatively infrequently. On the other hand, on a property where early, intensive dipping had not been carried out, very heavy infestations of ticks were present throughout the summer and autumn in spite of monthly dippings. This procedure of relating times of dipping to the ecology of the tick has been termed "strategic dipping". In the 1954-55 season, results obtained by intensive spring and early summer dipping were not comparable with those of the 1953-54 season. This appeared to be attributable principally to delayed or relatively ineffective dippings at critical times. Effective application of strategic dipping, as during the 1953-54 season, would reduce the need for acaricidal treatment of the cattle in the summer months when dipping is likely to be delayed by rainy periods.