Medication errors are a significant proportion of medical errors for patients in healthcare organizations. Little is known about the experiences of prelicensure student nurses who make medication administration errors. The purpose of this mixed methods study was to describe self-reported medication administration errors made by prelicensure student nurses, including error characteristics, related factors, patient outcomes, and student experiences of the error. Human Error Theory guided the study and served as a framework for interpreting the data. A survey was developed and sent to 1150 randomly selected registered nurses in Washington state. Of the 184 (16%) completed surveys that met inclusion criteria, 58 respondents (31.5%) reported that they made a medication error as a prelicensure student. The most frequent errors were the wrong time (19%), greater than prescribed dose (13%), and wrong monitoring (13%). Inadequate support/supervision (16%); inadequate communication with instructor, nurse, or patient/family (13%); distraction (12%); confusing medication administration record (10%), inadequate time to prepare and administer the medication (9%); and fatigue (9%) were the most common factors identified as contributing to the medication error. Patient outcomes as a result of the medication administration errors were identified by respondents as no harm to the patient (91%), temporary harm requiring interventions (5%), and harm requiring life sustaining measures (2%). Chi square analysis revealed no statistically significant relationships between medication error and type of nursing program (p = 0.42, chi2 = 2.82, df 3), gender (p = 0.65, chi2 = 0.21, df 1) or respondent age at the time of the survey (p = 0.57, chi2 = 1.97, df 3). The proportion of respondents reporting a medication error demonstrated no differences between junior and senior level students (p = 0.57). No statistically significant relationships were identified between the number of errors made by the respondents and type of program (p = 0.62, chi 2 = 1.80, df 3), respondent gender (p = 0.17, chi2 = 1.89, df 1), and respondent age at the time of survey (p = 0.37, chi2 = 3.11, df 3). Qualitative content analysis identified three themes: trauma related to making an error, 'owning' the error, and system complexity. Study findings have implications for nurse educators to (1) optimize student learning regarding medication administration, and (2) ensure patients' safety in the care of prelicensure student nurses.