N-phenylpiperazine compounds are a very large class of chemicals, and some of them have the ability to cross the blood-brain barrier due to the small size and the lipohilic nature. This group of compounds shows an interesting spectrum of biological activities. The chemical stability of the drugs determines the quality of the drug, affects safety, efficacy and storage conditions. The active compounds have diverse molecular structure and are susceptible to many variable degradation pathways, such as hydrolysis, oxidation, photodegradation, isomerization, elimination, dehydration and interaction with others substances. A hydrolysis degradation process is one of the most common destructive processes for chemical structures. It depends on various conditions e.g. temperature, pH and the... chemical properties of a substance. The aims of this investigation were to study the stability testing of 2-[(4-phenylpiperazino)methyl]-2,3-dihydro-5H-[1,3]oxazolo[3,2-a]pyridine-5-one, a new oxazolopyridonyl derivative of phenylpiperazine. A probable pathway of its chemical degradation was designated, based on the kinetic parameters and the identification products by the chromatographic methods.