The present invention provides [1,2,4]triazolo[1,5-c]pyrimidine derivatives or pharmaceutically acceptable salts thereof which have adenosine A.sub.2A receptor antagonism and are useful for treating and/or preventing a disease induced by hyperactivity of an adenosine A.sub.2A receptor, the derivatives being represented by formula (I): (wherein R.sup.1 represents substituted or unsubstituted aryl or a substituted or unsubstituted aromatic heterocyclic group; R.sup.2 represents a hydrogen atom, halogen, lower alkyl, lower alkanoyl, aroyl, substituted or unsubstituted aryl, or a substituted or unsubstituted aromatic heterocyclic group; R.sup.3 represents lower alkyl, lower cycloalkyl, substituted or unsubstituted lower alkanoyl, substituted or unsubstituted aryl, or a substituted or unsubstituted aromatic heterocyclic group; and Q represents a hydrogen atom or 3,4-dimethoxybenzyl).