This chapter provides illustrative examples of those areas of Spanish syntax in which corpora are widely used. The techniques of corpus linguistics allow for research into variability and for the identification of the patterns most frequently used. The studies that serve to illustrate the application of corpora to this aim are based on cognitive approaches or on Construction Grammar. The chapter presents corpus-based syntactic research with the emphasis on the quantitative and qualitative valency of predicative items, particularly verbal ones. More specifically, it discusses (i) the potential valencies of predicates of cognition, communication, physical contact, 151change, perception, sensation and evaluation, and (ii) specific classes of constructions, such as transitives or ditransitives, complex transitive constructions, passives, (pseudo-) reflexives and experiencer constructions. In addition to reviewing a number of studies based on samples taken from corpus concordances, the authors pay particular attention to studies originating in databases that provide morphosyntactic, functional and/or semantic annotation, such as bases de datos sintácticas (BDS) and Alternancias de Diátesis y Esquemas Sintáctico-Semánticos del Español (ADESSE). As regards the methodology used in the syntactic papers presented, qualitative analyses based on simple frequency data at the core of this chapter. However, studies containing multifactorial analyses, which measure the relative weight of heterogeneous factors in the grammatical choices that speakers make, are also taken into account.