Improvement of primate facilities is potentially costly, and is constrained by health and safety considerations and by limited experience in smaller units. During the last decade, most units have progressed from two-tier, single housing on grid floors, but there are still opportunities for refinements to reduce contingent suffering. The methodology of housing rhesus monkeys loose in rooms without cages has been documented in a video presentation. The animals have defined health status, but routine room maintenance and animal handling encourage close staff contact, generating health and safety concerns. The management changes have resulted in less aggressive, more-cooperative animals that are less stressed by capture. There are more natural behaviours, together with decreased animal and staff stress, resulting in better experimental models. The cages remain cleaner, releasing staff to spend more time on positive reinforcement training. There is better use of available space, and experimental immunology studies have been included within the breeding colony. The project has demonstrated a way of providing a management system that results in major benefits to animal welfare, staff morale and to the quality of the scientific studies undertaken. The methodology is now being used in an experimental unit housing animals for neuroscience. Continuing challenges include some social unrest within groups, managing animal health and maintaining high levels of personnel safety.