To date, the areal extent, carbon pools, rate of carbon accumulation, and role of peatlands of the former Soviet Union (FSU) in the terrestrial carbon cycle has not been fully recognized. This is a consequence of the fact that many peatlands in the FSU, especially noncommercial peatlands, were never studied and properly mapped. An estimate of the areal extent, carbon pools, and rate of carbon accumulation in peatlands of the FSU obtained by interrelating a number of regional databases and maps, including formerly classified maps, is presented herein. Commercial peatlands were categorized by regional type which facilitated an evaluation of their age and quality. Noncommercial peatlands were evaluated from classified regional topographic maps. Air photographs were used to identify peatlands of northern landscapes. The total peatland area of the FSU was estimated at 165 Mha (106 hectares) which was two times greater than the most recent estimates based on thematic maps. The peat carbon pool was estimated at 215 Pg C. Half of this amount was in raised bogs. The rate of peat accumulation varied from 12 g C m−2 yr−1 (polygonal mires) to 72–80 g C m−2 yr−1 (fens and marshes). The total rate of carbon accumulation in FSU peatlands was 52 Tg C yr−1. Carbon emissions from peat utilization in the FSU were estimated at 122 Tg C yr−1. Thus, at present, peat accumulation/utilization in the FSU is a net source of approximately 70 Tg C yr−1 to the atmosphere.