The aim of this in vitro study is to evaluate the shear bond strength of resin modified glass ionomer to dentin using one step self-etch adhesive. Moreover; the effect of pre-bonding and post-bonding moisture contamination of such restorative complex was studied.Methods: Eighty freshly extracted human molars were collected, cleaned and stored at 4°C in a solution of 1% chloramine, they were used within three months. The occlusal surfaces of all teeth were grounded flat to expose the necessary amount of dentin in order to obtain a flat surface on which a cylinder of resin modified glass ionomer was bonded. Artificial saliva was prepared for the purpose of this study. Samples were randomly assigned to eight groups in which each group consisted of 10 specimens. Three bonding procedures were evaluated: 1) no dentin conditioning (control), 2) poly-alkenoic acid conditioned dentin, and 3) Self-etching adhesive pre-treatment. The artificial saliva was applied either before or after dentin pre-treatment. After surface treatment, a cylindrical Teflon mold was placed on the sample in order to build cylinders of 2 mm hight with a flat base of 3 mm diameter. The resin modified glass ionomer was inserted into the mold in bulk. For shear bond strength testing, all samples were mounted on a computer-controlled materials testing machine (Model LRX-plus). The load at failure was divided by bonding area to express the shear bond strength in MPa. Statistical analysis of the results was performed. Results: The shear bond strength of resin modified glass ionomer to dentine showed an increase in case of using self eching adhesive even in the presence of moisture contamination. It also showed that: Shear bond strength of resin modified glass ionomer to dentine significantly decreased in case of moisture contamination without surface treatment.Conclusion: Self-etching adhesives improves the shear Bond strength of resin modified glass ionomer to dentin, One-step self-etching adhesives may perform effectively in humid environment and Irrespective of the bonding protocol, resin modified glass ionomer can bond to dentin in a relatively moist field.