The aim of teaching science at secondary school level is that of achieving the scientific literacy of all citizens. This must involve diverse objectives, among which may be found the development of procedural skills (thought, manipulative, communicative, etc.). The new curricula of many countries provide for these objectives. However, it is important to know to what extent the teaching staff consider them as true content to be taught. In this article, we analyse the opinions of secondary school teachers belonging to schools in north-western Spain with regard to how they value different types of procedures. Our findings show that the surveyed teachers establish differences between various procedural skills as far as the recognition of their presence in the classroom and their evaluation are concerned, although it may be said that they generally value procedural skills highly. These findings are discussed. In addition, the persistence of traditional conceptions in the teaching of science, as well as the difficulty of assuming that the changes promoted by new curricular approaches are addressed, are highlighted.