The aim of this study was to evaluate the effectiveness of using mobile phone short message service (SMS) to enhance knowledge of medications among nursing students. A quasi-experimental design was used. A convenience sample of 111 nursing students who were taking a pharmacology course at a university in southern Taiwan received an invitation to participate. The intervention group received learning materials by SMS twice per day for 10 days. Data were collected from 52 students in the intervention group and 54 students in the comparison group at baseline and at one week, two weeks and four weeks after the intervention. A generalized estimating equation (GEE) was used to determine the effectiveness of the intervention. The findings show a statistically significant difference between the two groups over time in the medication knowledge score. The students in the intervention group reported an above-average satisfaction level with this learning method; students reporting higher levels of satisfaction with the intervention had higher scores on medication knowledge. These results indicate that providing learning materials by SMS can significantly enhance nursing students' medication knowledge. (Contains 2 tables and 2 figures.)