OBJECTIVE: To assess students' development of aseptic technique skills through the use of a scoring rubric. DESIGN: A scoring rubric was developed to assess students in 6 skill areas of parenteral preparation. Areas were assessed as "likely harmful," "needs improvement," or "acceptable" according to developed criteria. Students were assessed at baseline and at the end of the fall and spring semesters. ASSESSMENT: Of 624 ratings given to 104 students at baseline and at the end of the spring semester, respectively, 51.1% and 88.9% were "acceptable," 17.9% and 7.6% were "needs improvement," and 30.9% and 3.5% were "likely harmful" (p < 0.001 vs baseline). The percentage of students receiving one or more likely harmful ratings decreased from 85.6% at baseline to 18.3% (p < 0.001). CONCLUSION: Use of the rubric successfully documented student improvement. It also identified areas that need additional emphasis in the curriculum.