The aim of the present study was to investigate neuropsychological test performance in children and adolescents with familial Mediterranean fever (FMF). A total of 88 children and adolescents aged 8 to 17 years were included, 52 with FMF and 36 healthy controls. After the participants were administered the Children Depression Inventory (CDI) and the Screen for Child Anxiety Related Emotional Disorders (SCARED), they completed the battery tests of the Central Nervous System Vital Signs (CNSVS), a neurocognitive test battery, via computer. The battery calculates seven domain scores (Memory, Psychomotor Speed, Processing Speed, Reaction Time, Complex Attention, Executive Function, and Cognitive Flexibility) and a summary score (Neurocognition Index [NCI]). A statistically significant difference between the FMF and control groups was found in six out of seven domains, where the scores of the participants with FMF were found to be significantly lower than those of the control participants (p <.05). Although the mean Reaction Time score of the participants with FMF was found to be lower than that of the control participants, the finding was not statistically significant (p >.05). The mean CDI and SCARED scores of the participants with FMF were found to be significantly higher than those of the control participants (p <.05). Low scores in the Processing Speed and Psychomotor Speed domains of the CNSVS were significantly correlated with higher SCARED scores (r = −.37, p =.01). Impaired cognitive functions should be taken into consideration in children and adolescents with FMF when assessing and managing this population.