Background The diagnosis of Specific Language Impairment (SLI) is very complex, given the variety of clinical pictures described in this disorder. Knowledge about the linguistic markers of SLI can facilitate its differentiation from the normal profile of language development. These markers can also be used as tools that may improve diagnostic. Aims To determine which psycholinguistic markers best discriminate Spanish-speaking children with SLI from children with typical language development. Method and procedure The performance of 31 Spanish-speaking children with SLI was analysed using a battery of 13 psycholinguistic tasks organized into two areas: phonology and morphosyntax. The performance of the SLI group was compared to that of two subgroups of controls: aged matched (CA) and linguistically matched (CL). Outcomes and results The data show that the SLI group performed worse than the CA subgroup on all 13 verbal tasks. However, the performance of the SLI group did not significantly differ from that of the CL subgroup on most (11/13) of the tasks. Stepwise discriminant analysis established the canonical function of three tasks (morphologic integration, sentence understanding and diadochokinesis) which significantly discriminated SLI from CA, with sensitivity 84% and specificity 90%. Conclusions and implications These results contribute to determining the psycholinguistic and clinical characteristics of SLI in Spanish-speaking children and provide some methods for screening assessment.