The purpose of this study is to identify and analyze the relationships that exist between mathematics anxiety and nurse self-efficacy for mathematics, and the medication calculation performance of acute care nurses. This research used a quantitative correlational research design and involved a sample of 84 acute care nurses, LVNs and RNs, from a suburban private hospital. The participants filled out a Mathematics Anxiety Scale, a Nurse Self-Efficacy for Mathematics Scale and also completed a 20-item medication calculation test. Significant practical and statistical relationships were discovered between the variables utilizing multiple linear regression statistics and commonality analysis. As the Nurse's Mathematics anxiety score increased the scores on the medication test decreased and the scores on nurse self-efficacy for mathematics scale also decreased. The demographic item of "Hours a nurse worked in one week" had the greatest significance. The more hours a nurse worked the lower their score was on the medication calculation test. This study agrees with others that nurses are not good at mathematics. This study also correlated that as the number of hours worked increased so did the medication calculations errors. And many nurses have a measurable level of anxiety about mathematics and dosage calculations and this may influence calculation ability. Suggestions for further research include refinement of instruments used in study, further differentiation of barriers to successful medication calculation performance, and testing of interventions used to teach, train and evaluate accurate medication administration in nurses. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]