The peso ley 18.188 (ARY; unofficially ARL; peso ley dieciocho mil ciento ochenta y ocho), usually known as either peso or, to distinguish it from the earlier peso moneda nacional, informally as peso ley, was the currency of Argentina between January 1, 1970, and May 5, 1983. It was subdivided into 100 centavos. Its symbol was $L, sometimes $. Its name comes from law 18188 which established it, effective April 5, 1969.

The peso ley replaced the peso moneda nacional at a rate of 100 to 1. It was itself replaced by the peso argentino at a rate of 10,000 to 1.

The history of the various successive Argentine currencies called peso is detailed in the article on the Argentine peso.

In 1970 coins were introduced in denominations of 1, 5, 10, 20 and 50 centavos. As inflation eroded the currency's value, higher denominations were introduced: 1 peso in 1974, 5 and 10 pesos in 1976, and 50 and 100 pesos in 1978.

Banknotes were issued in the following denominations:

• La Década Perdida (The Lost Decade)
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