A technique of regions’ economic development stability assessment has been stated. The technique is based on diagnosing of economic growth stability loss by an assessment of economic growth rate dispersion. The economic growth instability risk is estimated by an indicator reflecting a relative variation of economic growth rates. Regions of Far East Federal District: Republic of Sakha (Yakutia), Kamchatka Krai, Primorsky Krai, Khabarovsk Krai, Amur Region, Magadan Region, Jewish Autonomous Region, Chukotka Autonomous District, Sakhalin Region have been investigated. Statistical data during 2000–2011 have been used. It has been established that regions significantly differ ones from others on the periods of sustainable and unstable development and economic growth instability degree. It has been revealed that economy of most regions of the Far East Federal District develops unstably. An exception is Primorsky Krai which develops more stably. Economic development instability indicators significantly influence on a level of investments into region economy. On a sample of regions the economic development instability explains not less than 30% reduction of investment level, that allows consider economic development instability impact on investment climate in the region as significant.