Aflatoxins are metabolites produced by fungi (Aspergillus flavus and Aspergillus parasiticus) in high humidity environment in crops such as maize nuts and processed food. Aflatoxin contamination in food is monitored with strict regulations worldwide due to high toxicity of the compounds. Recently, several media reports revealed the exceed levels of aflatoxins found in peanut butters in the USA and Taiwan. Aflatoxins in food have been analyzed by LC/MS/MS using various sample pre-treatment methods. We describe a high sensitivity LC/MS/MS method for quantitative analysis of aflatoxins in peanut butters using QuEChERS sample pre-treatment procedure, as opposed to the use of immunoaffinity column or other methods for sample pre-treatment which are more expensive and tedious. High sensitivity and good recoveries were achieved using this LC/MS/MS method.