Many factors effect survey response rates and one is thought to be a respondent's awareness of the survey organization's name. In RDD telephone surveys, if a respondent has Caller ID, it may help a survey company to display its name. In 2004, we conducted a test involving Caller ID technology in Nielsen's RDD diary recruitment calling process. The objective was to determine the impact of displaying our name and phone number on the respondent's Caller ID display on the (1) telephone contact rate, (2) telephone response rate, and (3) subsequent mail survey response rate. Recent events have reinforced the importance of exploring the use of this technology, including: 1) the increasing popularity of home Caller ID use, 2) the increasing use of Caller ID as a screening device, 3) the proliferation of telemarketing calls, 4) the DNC list, 5) the recently enacted federal law that requires telemarketers to make a Caller ID number available (which respondents may be unaware that researchers are not subject to), and 6) new services which do not allow "out of area" numbers to even ring the phone unless the caller provides additional information. The telephone stage of the experiment was conducted in mid 2004. The Caller ID treatment was randomly assigned to 108,368 RDD telephone numbers throughout the entire U.S. Numbers in this sub-sample that reached households with Caller ID (estimated at approx. 30 - 40% of all U.S. households) had the words, "Nielsen Ratings" displayed. Another randomly assigned 242,173 RDD numbers served as the control group for which the Caller ID treatment was not used. The test results showed a significant increase in telephone response rates of 2.5 PP, but there was no significant impact on the response rate at the subsequent mail survey stage. These and other findings will be discussed.