One of the major duties of nurses is proper medication administration while maintaining patient safety, which requires sufficient knowledge and practice. Any gaps in knowledge used by nurses can lead to irreversible injury or death of the patient. This study is aimed to determine and compare the pharmacology knowledge and performance of nurses and nursing students in using the information resources in pediatrics wards. This descriptive observational study was performed on 300 nurses and nursing students. Sources of knowledge and performance of nurses and nursing students were analyzed with researcher-made tools to determine their pharmaceutical knowledge, sources of knowledge, and attitudes by independent t-test, chi-square, one-way analysis of variance, Pearson, and Spearman tests. Three hundred questionnaires were examined. The clinical experience of nurses and students was their most important source of information in drug challenges for 33.7% of the participants. About 24.6% of nurses obtained the required information from specialized books on pediatric medicine. About 17.1% of the participants attained their knowledge from multiple sources (e.g. various available sources such as the Internet, pharmacy books, software, and their experiences and colleagues), while electronic sources and the Internet were the sources of knowledge for 15.5% and 7.7% of the nurses, respectively. Concerning nursing students, 6.3% used books, 41.7% considered colleagues (clinical experiences), 20.8% employed electronic resources, 22.8% used the Internet, and 9.1% relied on multiple sources. There were significant differences in the knowledge and performance of the nurses based on their source of pharmacological knowledge (P < 0.05). Most of the resources used in the hospital are not up-to-date and evidence-base, and the majority of nurses tend to rely on their clinical experience or their collegues information for medication administration rather than reading books or searching for up-to-date approaches and information. Nursing students also trust nurses' clinical experiences more than other sources provided for them including books and Internet. Some action should be taken by the managers for boosting the nurses' tendency for using up-to-date information resources.