Abstract. Quality of Service (QoS) is a broad term used to describe the overall experience a user or application will receive over a network. A rough set based approach is used to design a modi?ed Cloud-QoS Management Strategy (MC-QoSMS). MC-QoSMS is a component of cloud broker that is used to allocate resources based on Service Level Agreement between users and providers for Infrastructure as a Service (IaaS)provisioning of cloud. Concept of reduct from rough set theory is used to allocate the best service provider to the cloud’s user with minimum searching time. The performance of the proposed system has been analyzed in terms of number of requests. It is reported that the system outperformed random algorithm by 25% and the round robin algorithm by 30% for 100 requests.