We report a two-year longitudinal study aimed at investigating the rate of access to numerical and non-numerical information in long-term memory and the functioning of automatic and effortful cognitive inhibition processes in children with arithmetical learning disabilities (ALDs). Twelve children with ALDs, of age 9.3 years, and twelve gender-age-matched controls were involved in the study. Rate of access was measured through digit- and letter-naming tasks, automatic cognitive inhibition was measured using a negative priming paradigm, and effortful cognitive inhibition was measured rating intrusion errors in a working memory task. Children with ALDs suffered from a deficit in the speed of activating both numerical and non-numerical information from long-term memory and in effortful inhibition mechanisms. No evidence for dysfunction of the automatic inhibition processes was found. (Contains 3 tables.)