Medication administration errors (MAEs) are among the key concepts of patient safety in clinical care settings that have long been the focus of study and exploration because they contribute directly to patient injury, death and health care costs. Medication errors are recurrent and expected to be a prolonged problem in the health care system. The administration of medication is predominantly an important part of nursing practice that has a dimension of quality of care and organizational performance. The study sought to assess nurses' medication administration errors at the general medical and surgical units. A descriptive cross sectional study design was used where stratified random sampling using the medical and surgical units as strata was used to proportionately recruit 100 Nurses. Each nurse was further observed twice during medication administration process making a total of 200 observations included in the study. Two tools were used to collect data for the current study. The interviewer administered medication administration errors questionnaire and a concealed medication administration observation checklist. Data was collected for a period of four months and analyzed using descriptive and inferential statistics to check for relations between variables. The study findings imply that the wrong rate of administration, the wrong time of administration and medication being administered after the order to discontinue was written were the highly perceived MAEs reported respectively as occurring 'most of the time' by 27%, 23% and 15% of the studied nurses. For observed MAEs, the wrong time error type had the highest estimated error rate of 51%, followed by the documentation error at 29% and technique error at 27.5%. There was statistical significant difference between the pharmacy reasons subscale of causes of MAEs and the age (F= 5.465, p=0.006), clinical experience (F=3.922, p=0.011) and type of shift (F=2.507, p=0.035) the nurse works most. Further, there was statistically significant mean differences between the medical and surgical units with regard to the medication packaging subscale (t=4.160, p=0.044). The findings also revealed negative significant correlation between the observed MAEs scores and the nurses' reported scores on types of IV & non-IV MAEs (r s =-0.266, p=0.007) and the pharmacy reasons subscale (r s =-0.266, p=0.046). Updating, developing, disseminating and implementing medication administration guidelines and protocols in the hospital settings is required. Nurses have to embrace the occurrence of MAEs as a patient safety indicator that should be viewed as an opportunity to learn and prevent MAEs through rationalized medication management protocols and guidelines.