Purpose: This study evaluated the effect of blood contamination and decontamination procedures performed at different stages of bonding, on the microtensile bond strength (μTBS) of an etch-and-rinse adhesive to dentin. Materials and Methods: Standardized cylindrical cavities were prepared in bovine incisors and were randomly divided into five groups, each one was treated using these experimental conditions-Control: etching-rinsing/bonding without blood contamination; Group 1: etching-rising/blood contamination/decontamination/bonding; Group 2: etching-rising/bonding/blood contamination/decontamination; Group 3: etching-rising/bonding/blood contamination/decontamination/etching-rising/bonding; and Group 4: etching-rising/blood contamination/decontamination/etching-rising/bonding. Specimens were prepared for μTBS and were evaluated both immediately and after 6 months of storage in distilled water. Results: Blood contamination significantly reduced the μTBS (P < 0.001). Groups 2 and 3 showed the lowest μTBS values, both for 24 h and 6 month aging. Conclusions: Blood contamination tested at any of the different stages of the bonding procedure showed a negative effect on the μTBS. Recovering adhesion of blood-contaminated dentin did not depend only on cleaning with distilled water.