The relationship between egg output and the weights and states of engorgement of two species of ixodid ticks Amblyomma variegtum (Fabr.) and Boophilus annulatus (Say) was studied, using over 3,000 female ticks of different sizes. Based on the average weights and numbers of eggs produced, guide indices are provided for the predictability of the oviposition potential in females of different weights. Linear correlation was noted between weights of the ticks and the weights and numbers of eggs they produced. The percentage by body weight of eggs produced by individual ticks did not however exceed 50 +/- 2%, irrespective of their states of engorgement. Arbitrary categorisation of the ticks on basis of their sizes ("states of engorgement") reflected on exponential increase in the rates of egg output.