Privacy and confidentiality are often of great concern to respondents answering sensitive questions posed by interviewers. Using the 1993-2010 General Social Survey, we examined trends in the provision of social security numbers (SSNs) and correlates of those responses. Results indicate that the rate of SSN provision has declined over the past three decades, that is, from about 60% in 1993-1994 to 20% after 2004. Although younger, unmarried, and less-educated respondents are more likely to provide SSNs, an indicator of trust toward others is not a significant predictor of SSN provision. Further, those who refuse to report their income and who receive an incentive are less likely to provide their SSN. Our findings have implications for studies involving sensitive questions as well as privacy and confidentiality issues.