A three day sample observation of card catalogue consultation by users at ISRO Satellite Centre (ISAC) Library has been made and results recorded. Users have been subsequently questioned about the purposes for which catalogue was consulted. The paper describes the card catalogue system of the library, the method followed and limitations of the study. The data in appropriate tables has revealed that classified catalogue is not used; Report Number Catalogue is least used and subject catalogue is consulted to the maximum. It is also found that more than half of the consultations of card catalogue are to locate documents, one-fourth is to interact with circulation system, one-tenth is to make a comprehensive search for references on a topic and rest for miscellaneous purposes. It is concluded, based on the results, that arrangement of charged out tray at circulation counter be changed to classified order and classified catalogue itself may have to be dispensed with
