This report describes a national telephone survey of randomly selected middle and high school principals to measure the impact of school-uniform dress codes on perceived level of school violence. In addition to measuring the impact of school uniforms on principals' perception of violence, selected variables such as region, gender, and educational level were measured to assess for significant differences in principals' perception of violence. The aim was to develop a study that addressed the issue of school uniforms in such a way that the results could be generalized to other middle and high school populations across the United States. In addition to examining the history of the first districtwide uniform dress code implementation, this study cited specific empirical inquiries that have provided support for and criticism against the use of school uniforms as an alternative in addressing the problem of school violence. A total of 141 school administrators within four geographic regional urban school districts were surveyed during the spring 1999 school semester. Parametric tests of statistical significance were utilized to measure the hypotheses under investigation. The findings of this study yielded significant differences among three of the variables measured. There are important implications resulting from this study that merit further inquiry regarding the impact of both school uniforms and the problem of school violence. (Contains 25 references.) (Author/TEJ)