The decisions made by infection control personnel affect both individuals and those in the broader patient population in a health care facility. In making the decisions required to provide an environment free of infectious risks, while maintaining the rights of individuals to attain optimal health outcomes, infection control practitioners are often confronted with ethical dilemmas. This article describes an ethical dilemma commonly faced in infection control practice, where the needs of one patient must be weighed against the needs of the patient population. A case study describing the decision to isolate an infectious patient is presented, highlighting the role that ethics plays in decisions made to control infection. A decision making framework is applied to ensure that the needs of both individuals and groups are considered. Resource considerations and the need to conform to basic microbiological and epidemiological principles are also considered. The various issues in conflict are described, analysed, resolved and rationalised. The use of a decision making framework can help to ensure that competing interests are carefully considered to produce an ethical, and optimal, decision.