The present study aimed to verify the visual deficit theory of dyslexia. the participants in this study consists of two groups from the fourth grade elementary boys, their ages ranged between 9 and 10 years, the dyslexic group (n =15) and the control group (n = 20). Participants responded to three tests of attention and visual processing: 1) continuous performance test to measure the focused and sustained attention, 2) William inhibition test to measure selective attention, 3) visual field attention test to measure the lateralization of simple visual stimuli. The results revealed several differences between the dyslexic and control group with regard poor selective attention, which appeared in the increased rate of interference errors and slow reaction times, while continuous and focused attention is not affected. Also it showed significant differences related to the slow reaction time to stimuli presented peripherally in left half of the visual field, which reflects is atypical lateralization of visual information among people with dyslexia. The results were discussed in the light of theoretical and applied consideration