Special features of morphological functional age development of the brain in children living in difficult climatic-geographical and social-economical conditions of the North (Archangelsk region) were studied. It was found that among 62 examined pupils of middle country school only in 10 persons (16%) amplitude-frequency and temporal-spatial EEG parameters are in accordance with passport age (European standards). 38 pupils (61%) have insignificant deviations such as insufficient regularity of EEG spatial-temporal pattern in frontal and temporal parts of the brain, increased theta- and delta-rhythms, absence of distinct "functional nuclear" in alpha range. In remaining 14 pupils (23%) EEG parameters suggest a more expressed retardation of mental development coupled with problems in the learning and inadequate behavior. Retardation of terms of morphological functional development of the brain in children--northerners equals 1.5 - 2 years, which is in accordance with terms of hormonal and physical development' retardation, described by different authors.