The aim of this paper is to provide a summary description of some grammar uses of the infinitive in Asturian, mainly in relative clauses and specifically in different patterns including de preposition: noun + de + infinitive (el llibru de lleer ‘The book that must be read’ o ‘the book that usually is read’) or article + de+ infinitive (Yera la fía la de faelo ‘his daughter was who should do it/have done it’, ‘his daughter was usually who did it’). Asturian differs from other romance languages by the possibility of personal infinitive (unlike French) with preverbal subject (unlike Spanish, Italian or Romanian). The widespread possibility of preverbal subjects within infinitive clauses make it close to Galician and Portuguese inflected infinitive, although in Asturian it does not correlates with the presence of person and number markers. On the other hand, Asturian shows a wider and more nuanced casuistic (from the semantic point of view) than, for instance, similar clauses in Spanish, with a complex gradation between noun and verbal infinitives and a more open range of syntactic structures. Differences between Spanish and Galician-Portuguese have been explained as a result of the preeminence of tense flexion in Spanish towards agreement in its western neighbors. Given our evidences, the intermediate situation of Asturian could also be explained by the relatively weakness of tense and the higher strength of determinative, specificative values, typically related to agreement. In general, both tense and preverbal placement of subjects strongly depend on the level of determinacy of infinitives, their subject or even their antecedents, if relative clauses. As for the first ones, through different syntactic structures, we can see how mainly the infinitives determined or controlled by articles license preverbal placement for their subjects. In a similar way, the common patterns of infinitive with a preceding subject usually occur with personal pronouns and human or high determined nouns. All of that leads to confirm the pre-eminence of agreement over tense. Meanwhile, some idiomatic structures considered show how temporal meaning tends to be displaced in infinitive clauses by aspectual, modal o contrafactual senses. This gives an idea of the weakness of tense in infinitive clauses and, otherwise, correlates to a higher tendency to preverbal subjects, under the conditions mentioned above. Finally, together with the semantics of verbs as a regulatory factor for the placement of subject, it can be seen how its position may strongly depend on certain kind of pragmatic assumptions of the discourse level.