Nowadays we can consider that the liquid chromatography methods are in considerable and dynamic development. This developing measure is not surprising at all if we consider the vast possibilities coming from the principle of this methods and the fascinating quantity of information provided by these methods, too. The aim of this paper is to present the steps of high performance liquid chromatographic method optimization, based on ion pair formation. The presented analytical method is a quick and reliable quantitative determination method of active ingredients and degradation products, in combined pharmaceutical products with analgesicantipyretic contents (acetaminophen, acetylsalicylic acid). This method can also be used also in process control, finished product release and stability studies to prove or to follow the quality of the product.