Abstract.1. Intraspecific aggression between termite major workers was used to obtain estimates of foraging distances for threeMicrotermesspecies in Sudan.2. Maximum foraging distance recorded forM.sp. nralbopartitus(Sjöstedt) in Khartoum was 11.3 m, giving an estimated minimum colony area of 100 m2. This is probably an underestimate. In the Tokar Delta, individuals from single colonies ofM. najdensisHarris were encountered up to 42 m apart, giving a colony area of 1390 m2.3. Intraspecific aggression could not be used reliably to distinguish members of different colonies ofM. lepidusSjöstedt. Soil barrier formation between groups of workers in petri dishes may be of use as a supplementary technique, especially for species showing no clear aggression.4. Experiments on isolated laboratory colonics ofM.sp. NrlepidusSjöstedt, established from alates collected in Khartoum, further confirmed the value of inter‐colony aggression for indicating colony identity.5. The complications introduced into estimation of subterranean termite foraging areas by overlap and interdigitation of colonies are discu