Behсet's disease (BD) is systemic vasculitis with multiorgan failure. According to the 1990 International Study Group for Behсet's disease (ISGBD) criteria, the main manifestations of the disease include recurrent mouth and genital ulcers; skin and eye lesions. Inflammatory diseases of the eye are diagnosed in 50–70% of patients with BD. Our described case illustrates the late diagnosis of BD in a 13-year-old girl, which led to severe eye disease (significantly decreased visual acuity of the left eye) 2 years after disease onset. The lesion of ocular posterior segments is the pathognomonic sign of BD. This symptom concurrent with other major manifestations of BD (skin and genital lesions) and the ethnicity of the patient (a resident of Dagestan, the region through which there was the Great Silk Road) should have promoted the earlier diagnosis of the disease.