This study compared the microtensile bond strength $({mu}TBS)$ of three single step adhesives to dentin. Occlusal superficial dentin was exposed in fifteen human molars. They were assigned to three groups by used adhesives: Xeno group (Xeno III). Prompt group (Adper Prompt L-Pop). AQ group (AQ Bond). Each adhesive was applied to dentin surface. and composite of same manufacturer was constructed. The bonded specimens were sectioned into sticks with an interface area approximately $1mm^2$, and subjected to $mu$ TBS testing with a crosshead speed of 1mm/minute. The results of this study were as follows; 1. The ${mu}TBS$ to dentin was $48.78pm9.83MPa$ for Xeno III. $30.22pm4.52MPa$ for Adper Prompt L-Pop. and $26.31pm7.07MPa$ for AQ Bond. 2. The mean ${mu}TBS$ of Xeno group was significantly higher than that of Prompt group and AQ group (p<0.05). 3. There was no significant difference between the ${mu}TBS$ of Prompt group and AQ group.