Abstract: The purpose of this research was to evaluate the effect of heat treatment on microbiological properties of mixed nectars based on cashew apple, mango and acerola. Ten different formulations were prepared according to simplex centroid design and subjected to heat treatment at 90°C for 1 min. Samples were collected before and after heat treatment and subjected to microbiological analysis (Salmonella sp., yeasts and molds, lactic acid bacteria and coliforms at 35 and 45°C). The mixed nectars were tested regarding to pH and acidity, concerning the relationship between the proportions of pulp and its influence on these results. The pasteurized product presented lower counts of lactic acid bacteria yeasts and molds and all the samples showed no coliform counts and absence of Salmonella 25 g. The formulations with high proportions of acerola pulp showed lower pH and higher acidity butthere was nodirect relationship with the results obtained in the microbiological analysis since, the nectars had similar values of pH and acidity.