The problem of distributed Dynamic Spectrum Access (DSA) using Continuous Time Markov Model (CTMC) in Cognitive Radio (CR) is considered in this paper. DSA is an approach which facilitates the opportunistic use of licensed spectrum for the unlicensed (secondary) users without casing harmful interference to the licensed (primary) users. In the proposed distributed DSA scheme, each secondary user perceives the spectrum dynamics as a CTMC and access the spectrum. This scheme is a heuristics based approach which makes use of the estimated spectrum idle-probability and the interference each user experiences, to iteratively update user statistics. Here the main objective of this scheme is to attain a best set of access probabilities based on instantaneous interference rather than attaining a single set of optimum access probabilities. Simulation results show the effectiveness of the proposed algorithm in terms of throughput and establish the access probability variations of the secondary users. Keywords—Cognitive Radio, CTMC, distributed scheme Dynamic Spectrum Access.