The masked priming paradigm was used to examine the role of the root and verb pattern morphemes in lexical access within the verb system of Arabic. Three groups participated in the study: grade 6 dyslexics, a reading-level-matched group and grade 6 normal readers. The first group consisted of: 28 grade 6 reading disabled (RD) students, 8 girls and 20 boys, age range 11.50-12.75 years. The second group consisted of: 30 normal readers from 6th grade, 21 girls and 9 boys, age range 11.33-12.25 years. The third group consisted of: 30 younger students matched to the RD students according to their reading level (4th grade) 19 girls and 11 boys, age range 9.33-10.25 years. All participants were native Arabic speakers. Four experiments were conducted using the masked priming paradigm of Forster and Davis (1984). The priming effect is obtained when processing a target word becomes easier as a result of a preceding primer. The testing procedures included presenting a front masking pattern (######) 500 ms before the appearance of the primer word. The participants' reaction times (RTs) and reading accuracy percentages were calculated separately for each group using 1-way ANOVA and contrastive t-tests were used to locate the source of variance between the different experimental conditions. The results indicated that the verb pattern did not significantly improve lexical access for normal or dyslexic readers. The root, however, significantly improved lexical access for younger and grade 6 readers but not for dyslexics. The results are discussed in relation to the factors that may affect the lexical status of Arabic morphological units and the organization of Arabic verbs in the mental lexicon. (Contains 3 tables and 2 figures.)