This paper reports on a successful experiment in the use of the telephone to screen a large urban population in order to identify a relatively small sub-sample. The problem at hand was the identification of a sample of wives of men working in the offshore oil industry. Alternative ways of identifying such a sample are discussed and reasons are given for the decision to use the telephone. The form of random digit dialling used in the study is described and the results of a pilot and the main screening exercise are presented in some detail. The final section of the paper takes a broader view of telephone interviewing. Data are presented on telephone coverage in the U.K., and the advantages and disadvantages of the telephone are assessed in relation to other data collection methods.