Conventional practice usually places demographic items at the end of a questionnaire. The thinking behind this practice is that demographic items are less important than topically-salient items, so a higher risk for item nonresponse is tolerated. A recent study by Teclaw, Price and Osatuke (2012) turn this logic on its head and found that item response for demographic items at the beginning of a questionnaire was higher than for the same set of items at the end of the survey. This finding raises the question of whether there are other approaches to stimulating high item response rates for demographic questions. Other studies (e.g., Messer et al., 2012; Lesser et al., 2012) have found item response rates are higher for those responding by web than for mail. This study extends previous research by exploring how a statement about the importance of answering the demographic items at the end of a survey might mediate the relationship between mode and item response rate. Experimental data from a customer satisfaction survey of Cooperative Extension Service clients are used for the study. Overall, the aggregate item response rate was significantly higher on seven demographic items for web respondents than for mail respondents. Among web respondents, the importance prompt treatment had a statistically significant higher aggregate item response rate than the no prompt treatment. Conversely, the aggregate item response rate for mail respondents with the importance prompt was not significantly greater than that for mail respondents without the prompt. These results suggest that an importance prompt is a viable strategy for reducing item nonresponse of demographic items, at least among web respondents. One explanation for the results might be that using an importance prompt on single-question screens drew more attention to the prompt than having the prompt embedded among questions on the paper instrument.