Spatio-temporal databases allow us to represent objects and phenomena from the real world which change position or shape as time elapses. Several query languages have been proposed during the last decade to deal with this type of database. Two of these languages have been compared in this paper: SQLST and Güting’s language. The comparison was based on criteria which have been applied to programming languages; however, they were adapted here to evaluate database query languages. The results led to concluding that both languages high degree of expressiveness may affect other criteria such as readability and simplicity, especially in the case of Güting’s language.