Since the mid-1990s cyclin-dependent kinase (CDK) inhibition has been the subject of an intense drug discovery effort in the pharmaceutical industry and in some academic institutions. Although only few compounds have at present progressed into human clinical trials, the prospect of finding safe agents useful in therapy, particularly in the cancer setting, is still positive. Some trends can be observed that witness the impact of recent findings in CDK basic biological research and technology advancements on the evolution of the patent literature on CDK inhibition. A patent literature review of small organic molecules as CDK inhibitors comprising the years 2001 – 2004 is presented here, as many of the major pharmaceutical companies have shown a continued effort in the field.