Fukuyama congenital muscular dystrophy (FCMD) is characterized by brain malformation caused by abnormal neurocyte migration, and presents with eye manifestations. Ninety percent of FCMD patients have the homozygote insertional mutation of the founder haplotype, and show typical progression of motor functional deficits. However, many patients with a heterozygote mutation show more severe motor and mental functional deficits. Although many prior reports on FCMD patients focused on the natural history of motor development, very few have referenced mental development. We surveyed 49 families of FCMD patients, who belonged to a patient's association, using a descriptive questionnaire. We classified our questions into 4 categories: 1) motor development, 2) social skills, 3) living skills and 4)language development. Forty-nine answers were collected, the median patient age was 7 years (range: 1.3 to 36 years). Twenty-eight patients had the homozygote mutation, 11 the heterozygote, and there was no answer for the other. All motor development milestones were delayed in all patients. Even though 80% of patients achieved single word communication, verbal development reflecting when the necessity for verbal communication arose, yielded a low evaluation in the social skill category. All patients achieved the skills needed for meal consumption more easily than other living skills such as changing their clothes. Many patients never obtained independent gait, while upper limb motions varied among patients. Furthermore, these motor function level affected their mental development. Communication with the others was also found to be an important factor for encouraging mental development. This study is a rare study focusing on the details of the mental development of FCMD. This survey is anticipated to help the families of FCMD patients as they strive to stimulate the development of their children.