The purpose of this study was to establish the effects of ultrasonic treatment of eggs on egg weight loss, hatchability, tibia mineral content, chick performance, and eggshell microbial activity. A total of 600 fresh eggs was randomly divided into 5 groups. Treatments were no ultrasound, 35 kHz for 5 min, 35 kHz for 10 min, 35 kHz for 15 min, and eggs sprayed with benzalkonium chloride solution at 0.02% (negative control). The eggshell microbial activity was reduced significantly at all ultrasonic treatments (P < 0.01). There were no significant differences among treatments for egg weight loss, hatchability, embryonic mortality, chick weight, or tibia Ca, P, K, Na, and Mg content. © 2012 Poultry Science Association Inc.