We analyzed whether Spanish-speaking children with Specific Language Impairment (SLI) showed deficits in lexical-semantic processing/organization, and whether these lexical measures correlated with standardized measures of language abilities. Fourteen children with Typical Language Development (TLD) and 16 age-matched children with SLI (8;0-9;11 years) participated. In a Lexical Decision (LD) task with implicit semantic priming, children judged whether a given speech pair contained two words (semantically related/unrelated) or a word-pseudoword. Children received a comprehensive language and reading test battery. Children with TLD exhibited significant semantic priming; they were faster for semantically related word pairs than for unrelated (p < .001) and than for word-pseudoword pairs (p < .0002). The group with SLI did not exhibit significant semantic priming, despite showing more variability. Children with SLI made significantly slower LDs [F(1, 26) = 4.61, p < .05, partial η2 = .15] and more errors [F(1, 26) = 4.16, p < .05, partial η2 = .13] than children with TLD. Mean response time across all LD conditions and the receptive vocabulary (PPVT-III) were significantly negativity correlated for children with SLI (r = -.71, p = .004). Children with SLI, especially those with the poorest language scores, showed a semantic-lexical deficit and a weakness in lexical-semantic association networks. Their performance on the LD task was significantly slower and poorer than for children with TLD. Increasing a child's vocabulary may benefit lexical access.