Malpractice in preparation and administration of intravenous (IV) medications has been reported frequently. Inadequate knowledge of nurses has been reported as a cause of such errors. We aimed to evaluate the role of nursesʹ education via installation of wall posters and giving informative pamphlets in reducing the errors in preparation and administration of intravenous drugs in 2 wards (ICU and surgery) of a teaching hospital in Tehran, Iran. A trained observer stationed in 2 wards in different work shifts. He recorded the nursesʹ practice regarding the preparation and administration of IV drugs and scored them before and after the education process. 400 observations were evaluated. Of them, 200 were related to before education and 200 were related to after education. On a 0-10 quality scale, mean ±SD scores of before and after education were determined. Mean ±SD scores of before and after education at the 2 wards were 4.51 (±1.24) and 6.15 (±1.23) respectively. There was a significant difference between the scores before and after intervention in ICU (P