The present invention relates to novel [1, 2, 4]triazolo[1, 5-a]pyrimidin-yl derivatives as inhibitors of phosphodiesterase 2 (PDE2). The invention is also directed to pharmaceutical compositions comprising the compounds, to processes for preparing such compounds and compositions, and to the use of such compounds and compositions for the prevention and treatment of disorders in which PDE2 is involved, such as neurological and psychiatric disorders.