The current CAA requirements for routine electrocardiographic surveillance of flyers is outlined, and the need for care in recording techniques is stressed. Electrocardiographs should meet current standards and be in good repair. Exercise electrocardiograms should not be employed routinely, except possibly for flyers over 50 years of age engaged in single-pilot commercial operations. Exercise tests are of value for individuals with equivocal symptoms or equivocal repolarization changes but the results should be interpreted as far as possible on the basis of probability analysis: to report tests as 'positive' without amplification and with implication of high predictive accuracy is unsatisfactory. The techniques of effort testing should be standardized, should be conducted with scrupulous attention to detail, and should be performed only in centres specified and approved for the evaluation of pilots' fitness to fly.