The currency abbreviation or currency symbol for the Mauritanian ouguiya (MRO), the currency for Mauritania. The Mauritanian ouguiya is made up of 5 khoums (Arabic for "one fifth") and is often presented with the symbol UM. Khoum and 1 ouguiya coins are rarely used in Mauritania, do to their low value. 

|||The Mauritanian ouguiya was first seen in 1973 when it replaced the CFA franc, the currency of the twelve formerly French controlled African countries, at a rate 5 to 1. The ouguiya, along with the Malagasy ariary (the currency of Madagascar), is one of only two currencies in circulation today that is non-decimal based. Both are divided into 5 sub-units rather than ten.