The purpose of this study was to determine whether mathematical drills enhanced the ability of students of nursing to calculate drug dosages accurately. First year students were drilled and then tested over the next 2 years in drug calculations. It was found that repeated drilling improved students' ability to calculate drug doses but that this skill level diminished over time, in some instances to predrill levels of accuracy. An increase in the number of correct calculations was noticed in the two semesters in which students had a clinical placement leading the authors to conclude that, contrary to previous findings, work experiences do enhance the ability to calculate medication dosages. As safety and competency are essential in those areas of nursing practice which depend on mathematical ability, educational strategies which develop and retain mathematical skills are needed.