Brazil's benchmark Bovespa index fell 0.48 percent to close at 47,229.59.
News that troubled Brazilian oil firm OGX Petroleo e Gas Participacoes SA would shelve development at some of its oil fields weighed on the Bovespa index.
Seeking to ease investors' concerns that it may collapse, OGX, controlled by Brazilian billionaire Eike Batista, announced on Monday it would suspend development at three offshore oil fields.
Shares of the Rio de Janeiro-based company led losses, dropping 29.11 percent to 0.56 reais, their biggest one-day decline on record.
Chile, stocks fell after socialist presidential candidate Michelle Bachelet won a resounding primary election victory on Sunday.
Chile's IPSA index fell 1.88 percent to close at 3,953.87. Retailer Cencosud led losses, with shares falling 3.93 percent.
Mexico's IPC index gained 1.36 percent to close at 41,176.80 points, reaching its highest level since May 31, despite news that manufacturing slowed in June to a 27-month low . The IPC had not risen for five consecutive days since late March.