Previous studies have shown that needle injections are very stressful for children. This study examined if a needleless injection system would be associated with lower anxiety levels in children by comparing children's responses to a traditional needle injection to their responses to the Biojector, a needleless system. Seventy-four sixth-grade students of two public middle schools, all scheduled to receive the Hepatitis B vaccine, were enrolled. The study used a cross-over design. The children's anxiety levels were measured both before and after each of the two types of injections using the Spielberger State Trait Anxiety Index for Children (STAIC). Data analysis found no significant difference in levels of anxiety associated with the Biojector injections when compared with anxiety levels associated with needle injections. When asked to choose the injection method for their third injection, however, students showed a preference for the Biojector (61%), which indicated a trend towards significance (p = .08).