The aim of this study was to evaluate the microtensile bond strength of two all-in-one self-etch adhesives applied to sound and caries-affected dentin with four different application techniques. Forty extracted third molars with occlusal caries were randomly divided into four groups for G-Aenial Bond and S3 Bond: (1) according to manufacturer's instructions; (2) with acid etching before applying adhesives; (3) doubling adhesive application time; and (4) doubling adhesive coating. Teeth were sectioned to obtain 1-mm-+/- 0.2-mm-thick dentin sticks and subjected to a tensile force. For G-Aenial Bond, doubling the time and application of two consecutive coats produced significantly higher strength than that obtained by following manufacturers' instructions and acid etching application to sound dentin. Prior acid etching and application of two consecutive coats to caries-affected dentin generated significantly higher bond strength than that using other techniques. For S3 Bond, there was no significant difference between application techniques in caries-affected dentin. For sound dentin, double-time application of S3 Bond produced significantly higher strength than application according to the manufacturers' instructions. Compared to the application according to manufacturer's instructions, acid etching before applying adhesives, doubling application time, and doubling the coating had a positive effect on bond strength to caries-affected dentin for all-in-one adhesives.