A mark–release–recapture of Culex pipiens pallens was conducted in an urban area of Japan during June 26–29, 2007. Larvae naturally occurring in rain gutters were collected and reared to adults in a laboratory. A total of 10,183 emerging female Cx. pipiens pallens of 4–8 days old were marked with fluorescent dye and released from one site. Recapture was made on 4 consecutive days using 41 Centers for Disease Control and Prevention traps with 1 kg of dry ice and human landing collection, and 121 marked females were recaptured. The overall recapture rate was 0.01. The mean distance traveled by the recaptured females was estimated as 470, 287, 326, and 517 m on days 1–4, respectively. The maximum flight distance of host-seeking Cx. pipiens pallens was estimated as 1,217 m based on the relationship between distance from the release site to the collection site and the total number of recaptures/traps. The population size of female Cx. pipiens pallens in the study area was estimated as 100,904 ± 8,509. The size of operational area for the control of Cx. pipiens pallens in urban area is discussed.