Record has established that there is issue of organisational citizenship behaviour in public health service sector in Taraba State which has affected the functionality of the sector. It is on this note that this study examined the moderating role of perceived organisational justice on the relationship between diversity management and organisational citizenship behavior in public hospital. The study used cross sectional research design and the instrument for collecting data is via questionnaires with the help of research assistants, the population of the study is 1900 and the actual sample for data analysis is 315. The result of the analysis has proven that, individual diversity management has no significant effect on employee organisational citizenship behavior both on direct and on an interacting relationship. However, organisation diversity management has a positive and significant effect on citizenship behaviour both on direct and indirect relationship respectively. Base on the findings of the study it was recommended that management and stakeholders of public health care sector should take both individual and organisation diversity into due consideration at all levels of health sector, so as to motivate employee of this sector to engage on positive behavior such as organisational citizenship behavior which will in turn improve the performance of this sector as a whole.