Estimates of the absolute size of a domestic population of Aedes aegypti aegypti (L.) were made in the Rabai area of Kenya, based on a single release, followed by either single or repeated recaptures. From single recapture within 24 h of release, the size of the female Ae. a. aegypti population in the Shauri Moyo village was estimated by the Lincoln index to be 365. Using a single release and repeated recaptures, population size was estimated by Jackson's positive method to be 337. Depletion of the unmarked females by daily removal sampling provided us with two additional, direct estimates of the size of the village population (451 by Kano's method and [464 +/- 18.9 SEM] by the Moran-Zippin method). The longevity of marked females was at least 9 d. The day-to-day movement of marked mosquitoes revealed the dispersal pattern of Ae. a. aegypti among houses clustered within different distance zones. Marked mosquitoes reached all houses of the village within 24 h of release. After 5 d, the dispersion of both marked and unmarked mosquitoes among houses was similar.