Clopidogrel bisulphate has quite low bioavailability (40-50%). It was aimed to increase its bioavailability by designing a controlled release dosage form of clopidogrel, which is different from available current dosage forms in the market. There are also some attempts to overcome patent protection of clopidogrel by combination of active substances or preparation of controlled release tablets. Therefore, it was also aimed to determine in vitro and in vivo properties of controlled release clopidogrel tablets. The amounts of releases from formulations were subjected computer program and effects of components in the formulation on release were investigated (INFORM v. 3.7 and FORMRULES, Intelligensys Ltd). Two sustained release formulations and innovator product were selected and their effectiveness was compared by in vivo tests in rabbits. In conclusion, proposed controlled release formulations were found to be an alternative and to be more effective for longer periods than the commercial one.