The present study aimed at investigating and comparing patients suffering from β-thalassemia (β-thal) minor with normal individuals in regard to their performances in the short version of the Wechsler Adult Intelligence Scale (WAIS) test. Patients with β-thal minor are carriers of β-thal genes. They have mild microcytic and hypochromic anemia and are usually asymptomatic. In this cross-sectional study, a total of 60 individuals were divided into two equal groups of β-thal minor and normal subjects; they were then studied by the WAIS subscales. The mean performance scores of the normal group in the subtests of arithmetic and vocabulary (p <0.01) and picture completion (p <0.05) were higher than those of the thalassemia group. The mean performance score and ability of the normal group on the verbal scale was higher in comparison to the thalassemia group (p <0.05), while on the non verbal scale, there was no significant difference between the two groups. It can be concluded that β-thal minor negatively influences verbal fluency, reasoning and conceptualization, and sequencing tasks, perceptual skill, prediction of social situations and abstract thinking.