Purpose: The purpose of this study was to investigate in vitro the effect of salivary contamination on the microleakage of resin composite restorations placed with a self-etching adhesive in primary teeth. Methods: Fifty-six extracted primary molars received standardized Class V preparations. The teeth were assigned to 7 groups (n=8): 1-layer and 2-layer application of the self-etching primer (Clearfil SE Bond) with no contamination (groups 1 and 2, respectively); saliva, SE primer, and drying (group 3); SE primer, drying, saliva, and drying (group 4); SE primer, drying, saliva, and rinsing/drying (group 5); SE primer, drying, saliva, drying, SE primer, and drying (group 6); and SE primer, drying, saliva, rinsing/drying, SE primer, and drying (group 7). For all specimens, the bonding agent (SE adhesive) and a composite were applied. After thermocycling and immersing in basic fuchsin, the teeth were sectioned and evaluated under a stereomicroscope. Data were analyzed using Kruskal-Wallis and Mann-Whitney tests. Results: The mean occlusal and gingival microleakage for groups 4 and 5 were significantly higher than that of groups 1 and 2 (P<.04). No statistically significant difference in microleakage among groups 1, 2, 6, and 7 was found (P=.09). The degree of microleakage in the gingival margins was significantly higher than that of occlusal margins (P=.027). Conclusions: The self-etching adhesive was not sensitive to saliva when contamination occurred before primer application. (Pediatr Dent 2009;31:334-9) Received March 2, 2008 vertical bar Last Revision August 19, 2008 vertical bar Revision Accepted August 28, 2008