Purpose – This study tries to examine how Perceived Instrumentality Organizational (The extent to which employees feel that their display of OCB will help in contributing to organizational operations and achievement of organizational objectives) and Perceived Instrumentality Individual (the extent to which employees perceive that their display of OCB will help in achieving Individual Objectives and benefits) are related to employees display of OCB and how these perceptions mediate the relationships between Perceived Organizational Support, Job Satisfaction, Justice Perceptions and OCB.Design/methodology/approach – A structured questionnaire was filled by a sample of 542 respondents from the pharmaceutical organizations located in Rawalpindi – Islamabad region of Pakistan. The data was analyzed with the help of SPSS and complete model testing was done with the help of AMOS.Findings – Results show that Perceived Instrumentalities Organizational and Individual partially mediate the relationships between Job Satisfaction, Perceived Organizational Support, Justice Perceptions and OCB. It was found out further that the mediating effect by Perceived Instrumentality Individual is more than that of Perceived Instrumentality Organizational. That leads us to conclude that the employees of the sector under study perceive individual benefits as more important than the organizational benefits.Practical implications – Effective Organizational Justice, Support and Job satisfaction can contribute to the development of stronger perceptions of Instrumentalities (Organizational and Individual), that in result can lead to a greater OCB. As it is known that beliefs and perceptions change with the time and experiences so a longitudinal or experimental research in future may be conducted to bring a definitive conclusion on the casual directions suggested in this study.Originality/value – The use of OCB specific meanings as mediators over the relationship between OCB and JS, JP and POS is unique to this study. The sector considered –Pharmaceutical- also adds to its originality and value.