Objectives: To measure microleakage around zirconia crown margins cemented with self-adhesive resin or resin modified glass ionomer (RMGI) cement after ultrasonic scaling. Methods: 16 molars were prepared for crowns (margin 0.5 mm coronal of cementum-enamel junction). Preparations were digitally scanned and zirconia crowns milled. Specimens were divided into two groups (n = 8): self-adhesive resin (RelyX Unicem 2) or resin modified glass ionomer (RMGI) (RelyX Luting Plus) cements. After cementation, specimens were ultrasonic scaled with a piezoelectric device (60 s, hand pressure). After thermocycling (20,000 cycles/5-55°C), specimens were immersed in 5 wt% fuchsine dye before sectioning bucco-lingually. Microleakage was examined under 40× light magnification. Statistical comparisons were made using a paired t test and a two-sample t test (α =.05). Results: Ultrasonic scaling did not alter microleakage at the margins of crowns (P =.31). There was no significant difference in microleakage of scaled and untreated margins with the use of different cements (P =.21). The amount of microleakage around margins that were scaled was not significantly different between cements (P =.14). Untreated margins of crowns cemented with RelyX Luting Plus showed a significantly higher microleakage than those cemented with RelyX Unicem 2 (P =.005). Conclusions: Piezoelectric ultrasonic scaling did not increase microleakage at the margin of zirconia crowns cemented with self-adhesive resin or RMGI cements. Clinical significance: Piezoelectric ultrasonic scaling around zirconia crowns did not impact marginal microleakage cemented with self-adhesive resin or RMGI cements.