This study evaluated the effect of a casein phosphopeptide-amorphous calcium phosphate based paste (MI Paste) on the microshear bond strength (MSBS) of different simplified etch-and-rinse adhesive systems on enamel. Roots were removed from 90 bovine incisors, and the facial enamel was ground flat. Teeth were randomized into nine groups, according to the enamel pretreatment (without or with application of MI Paste for 1 or 2min) and the adhesive system used (Single Bond, Stae, or Ambar). Composite cylindrical blocks (2mm heightx1mm diameter) were built, stored in water for 24h, and subjected to the microshear test in a universal testing machine with a load of 0.5mm/min. Failure modes were analyzed using scanning electron microscopy. Data were submitted for statistical analysis by a two-way ANOVA, followed by multiple comparisons with Tukey test (alpha=5%). The Ambar group presented the highest MSBS values. Pretreatment with MI Paste for 2min improved bonding in the Single Bond and Stae groups. In all groups, adhesive failures were most frequent. In conclusion, Ambar presented better performance and did not need any pretreatment. The enamel MSBS of the other simplified adhesive systems was improved by the pretreatment with MI Paste, depending on the time of application.