Aspects of the outdoor activity and distribution of the smokybrown cockroach,Periplaneta fuliginosa(Serville), were studied during a 14-day period in July 1984 in Houston, Tex. Daily trapping revealed an age-class distribution of 27.2% adults (260 females : 244 males) and 72.2% nymphs (630 small : 475 medium : 214 large). Trap-catch was significantly lower following rains and correlated to the time when it rained. Rain early in the day resulted in higher trap-catches than rains occurring later in the day. The mark-recapture technique was used to estimate adult population size, movement, and home range. Of 240 females and 206 males marked and released, 12.1% and 7.3%, respectively, were recaptured at least once. A mean of 338 female and 386 maleP. fuliginosawas estimated living on the 0.23-ha study site. Of recaptured adults, 34.3% of the females and 58.8% of the males moved at least 2 m. Mean circular home ranges were 107 m2for females and 280 m2for males. Traps located near harborage sites caught>70% nymphs, whereas other traps caught<43% nymphs.