Background: Language and intelligence are brain superior functions and their development is vital for school and future work performance. Objective: To establish the correlation between language and intelligence, in order to identify possible factors involved in preschoolers of low socioeconomical status. Methods: Prospective and blind study that performs specific language tests, audiometry, WPSSI and pediatric-neurological examination to all children between 3-5 year-old attending a daycare, belonging to families of low socioeconomical conditions at the Metropolitan Región of Chile, during 2007. Children with major diseases, explaining language difficulties (LD) were excluded. Results: 61 preschoolers, in which 22 (36%) LD were identified. Cognitive performance presented a normal distribution (mean 92,69 +15). There was a significant correlation between intelligence and language (p 0.002). Children with LD had lower cognitive performance, both in verbal (p 0.004) and in manual tests (p 0.0007). The family history of LD or learning difficulties and history of developmental delay were associated with a lower language performance (p 0,05 and p < 0.0000, respectively). Children of mothers with superior studies showed better scores in their cognitive potential (p 0.0079). Conclusión: Language and intelligence are significantly associated. Biological and hereditary factors were correlated with LD, whereas social factors (ex: maternal education) were associated with cognitive performance. These findings should be considered in the planification of health politics related with children development, implementing multidisciplinary strategies.