A new RP-HPLC method was developed and validated for the determination of an anti-thrombocythemic agent anagrelide in pure and pharmaceutical formulations. The separation was achieved on Peak HPLC instrument equipped with a LC 20AT pump and variable wavelength programmable UV-visible detector SPD-10AVP and a Chromosil C18 column (250 mm x 4.6 mm, 5μ) column. Methanol, acetonitrile and water in the ratio 80:15:05(v/v/v) was used as mobile phase at a flow rate of 1.0 ml/min and detection of the component was carried out at a wavelength of 260nm. 20μl of the standard or sample has been injected into the column through Hamilton syringe and the chromatogram was recorded. The retention time of anagrelide was found to be 4.46min. The plot was linear in the range of concentration 20-120μg/ml. The drug was subjected to forced degradation under different conditions such as UV light, Sun light, acidic, basic, thermal and oxidation. The drug was found to be stable in aqueous, basic and thermal conditions where as it was decomposed to some extent in the presence of acidic, peroxide, UV light and Sun light. The developed method was found to be simple, precise, accurate, rugged and robust and hence it can be used as an alternative method in assay of the anagrelide in any pharmaceutical industries.