A need exists for research that contributes to estimating the risk factors associated with the management of outdoor cats (Felis silvestris catus) and addresses the lack of such surveys in Brazil and other Latin American countries. With this in mind we aimed to: i) identify the causal factors affecting the practice of owners allowing their cats to roam freely and; ii) evaluate potential welfare risks associated with the allowance of outdoor access, based on cat owners’ reports. An online questionnaire consisting of 25 questions was answered by 8,485 Brazilian cat owners and logistic regression models used to obtain odds ratios. A number of the factors significantly related to owners allowing their cats to have outdoor access were unneutered cats, the manner in which the cat was acquired, residence in rural areas, the number of cats owned, the presence of other pets in the house, younger owner age, owner declaration of not being responsible for the cat, owner perception about the role of the cat in the house, owner knowledge about cats’ potential for transmitting diseases, a lack of knowledge about zoonoses, and a lack of knowledge regarding toxoplasmosis. The practice of allowing outdoor access was associated with significantly higher odds of owners reporting several welfare issues, such as frequent flea contamination, sporotrichosis, going missing, poisoning, mistreatment, and accidents. We conclude that the practice of allowing outdoor access, as reported by 37.1% of our respondents, may result in risks to feline welfare. Increasing public awareness through campaigns that highlight the risks associated with outdoor access would improve feline management practices and welfare.