Nonprescription drug use among university students was investigated using survey and behavioral diary methodologies to assess usage of nonprescription drug use and to compare survey and diary methodologies. Surveys were completed by 183 students (136 females and 47 males) that asked how often they used nonprescription drugs and what those drugs were. Of these participants, 61 (53 females and 8 males) voluntarily completed behavioral diaries for nonprescription drug use for a three week period. Survey data showed 83.1% of participants used nonprescription drugs in the past week, with pain relievers being the most common drug used. There was a significant correlation between the number of times participants reported using nonprescription drugs on the surveys and what the participants reported in their diaries, with no differences in the mean number of uses between survey and diary. This indicates that participants can recall information about their medication-taking behavior with some accuracy. Behavioral diaries were also able to show some of the misuse that is associated with using nonprescription medications. In most cases of misuse, too large a dose was taken. Students should be provided with information about the possible long- and short-term effects of these medications.