This study examined the relationships between personality traits, and types of online use patterns with instant messaging risk-taking. A sample of undergraduate college students completed an online survey measuring extraversion, risk-taking personality trait, instant messaging use type, frequency of instant messaging and two variables for instant messaging risk-taking: personal information risk and download file risk. A structural model was used to present and test the hypothesized relationships between these variables. Results suggest that students with low extraversion scores have higher risk of sharing personal information with strangers through a direct relationship between the variables, but that students with high extraversion scores also have an increased risk of sharing personal information with strangers and downloading files from strangers indirectly by a mediated relationship through instant messaging use type. Further, students who were categorized as using instant messaging software for many different types of use also had higher scores on personal information risk and download file risk.