Literature concerning the relationship between crowding (inside and outside the home) and health is reviewed. Attention is then focused on the association between internal density and psychological health in women. This relationship is investigated using data from a community survey conducted in West London in 1977. Our findings indicate a J-shaped relationship between internal density and psychological symptoms: that is, low as well as high levels of crowding were detrimental to psychological health. This pattern was found to persist after six possible intervening variables were controlled for. Possible explanations for these findings are discussed and lines of further research indicated.