Keeping shared toilets clean is a key public health challenge household users face in urban slum settlements of most developing countries. This paper provides insights on the cleanliness of households' shared toilets and the factors that influence their cleanliness, as well as influencing the inclination of the users to keep them clean. Subjects and methods: This analysis is part of a cross-sectional study conducted in 50 randomly selected slums in Kampala, Uganda between October and November 2010. A total of 1,500 respondents were interviewed, using a semi-structured questionnaire. Results: Out of 1,019 respondents using shared toilets, less than 12% reported having very clean toilets. Some of the significant factors influencing the cleanliness of shared toilets are: the ease or difficulty in keeping shared toilets clean, the number of households sharing a toilet room, effortful cleaning behaviour and cleaning intention on the part of the users. Conclusion: The findings show that most slum dwellers use toilets that are not hygienic.