The tick infestation patterns observed during 1966–73 are described for wild animals and cattle on the northern plateau of north-eastern Zambia, the eastern plateau and the intervening Luangwa valley. The seasonal periodicity of adult Amblyomma sparsum Neum., as observed on buffalo, was similar to that of A. variegatum (F.). Five major depart ures from the patterns of infestation previously found in the Central Province were observed. Boophilus decoloratus (Koch) was partially or totally replaced on cattle by B. microplus (Can.).Rhipicephalus appendiculatus Neum. although present on wild fauna in the valley, was absent from cattle on the eastern plateau. R. evertsi Neum. was absent from much but not all of the northern plateau and occurred in very low numbers only on the cattle of the eastern plateau, yet was present on the wild fauna of the Luangwa valley. Hyalomma marginaturn rufipes Koch was practically absent from cattle on the northern and the eastern plateaux and from the wild fauna, except buffalo, of the valley; H. truncatum Koch was abundant on cattle on the northern plateau and on the wild fauna of the valley, but on the eastern plateau cattle it occurred in low numbers only. A. pomposum Dön, was found on cattle in one area of the northern plateau, the only specimen of Amblyomrna on that particular herd. These anomalous findings are discussed in relation to the situation elsewhere in Zambia and in neighbouring territories.