Negotiations were expected to produce a series of economic agreements in areas ranging from agriculture to crude oil processing.
Ahmadinejad is on a tour of Latin America, visiting countries controlled by leftist governments and critical of Washington.
The Iranian leader began his tour on January 14 in Caracas, where he met with Venezuelan President Hugo Chavez, hailing him as an ally.
Chavez said Venezuela and Iran -- both oil-exporting nations -- will back cuts in OPEC output to world markets in order to support prices.
Chavez added the two countries had agreed to use money from a joint $2 billion fund to invest in friendly countries. This, Chavez said, would help free them from U.S. domination.