Unlike most other European capitals much of urban and suburban London is frequented by foxes. For five years, litters of fox cubs were tagged in West London and their dispersal studied. Aerial photographs were examined to aid litter location. Twenty-five per cent of the litters found were under garden sheds with raised wooden floors. Sixteen per cent of tagged cubs have been recaptured. Mean dispersal distances were 7.9 km for males and 3.1 for females. Most of the observed cub dispersal was away from the centre of London towards rural areas. Immigration from rural areas into the study area was not recorded. Adult fox population density, estimated from the number of litters found, was a minimum of 2.06 foxes per square kilometre. The significance of suburban and urban fox population densities and their dispersal patterns are considered in relation to the epidemiology of wildlife rabies.