The Bureau of Mines investigated the potential availability of magnesium from 45 properties in market economy countries (mec's). The 38 significant deposits evaluated have demonstrated resources of approximately 29 billion short tons (st) magnesium-bearing material containing 416 million short tons (mmst) magnesium oxide (mgo). Using data it gathered, the Bureau determined the magnesium production potential for each property including a 15-pct rate of return on invested capital. Total and annual availability assessments for the next 30 yr were completed for magnesium (mg) metal, dead-burned mgo, and caustic calcined mgo. At a January 1984 market price of $1.34/Lb mg metal, the propertiesevaluated could economically produce an estimated 13 mmst mg metal. At a market price of $400/st nonmetal magnesium product, these properties could economically produce 109 mmst deadburned mgo and 43 mmst caustic mgo. These properties could produce approximately 301,000 st mg metal, 3.0 Mmst deadburned mgo, and 430,000 st caustic mgo annually at current full production levels and 1984 market prices until at least the year 2000. Total 1984 mec production assessed in this study was 153,000 st mg metal and 4.3 Mmst nonmetallic mgo products.