OBJECTIVE Drug administration errors were the second most frequent type of medication errors, after prescribing errors but the latter were often intercepted hence, administration errors were more probably to reach the patients. Therefore, this study was conducted to determine the frequency and types of drug administration errors in a Malaysian hospital ward. METHODS This is a prospective study that involved direct, undisguised observations of drug administrations in a hospital ward. A researcher was stationed in the ward under study for 15 days to observe all drug administrations which were recorded in a data collection form and then compared with the drugs prescribed for the patient. RESULTS A total of 1118 opportunities for errors were observed and 127 administrations had errors. This gave an error rate of 11.4 % [95% confidence interval (CI) 9.5-13.3]. If incorrect time errors were excluded, the error rate reduced to 8.7% (95% CI 7.1-10.4). The most common types of drug administration errors were incorrect time (25.2%), followed by incorrect technique of administration (16.3%) and unauthorized drug errors (14.1%). In terms of clinical significance, 10.4% of the administration errors were considered as potentially life-threatening. Intravenous routes were more likely to be associated with an administration error than oral routes (21.3% vs. 7.9%, P < 0.001). CONCLUSIONS The study indicates that the frequency of drug administration errors in developing countries such as Malaysia is similar to that in the developed countries. Incorrect time errors were also the most common type of drug administration errors. A non-punitive system of reporting medication errors should be established to encourage more information to be documented so that risk management protocol could be developed and implemented.