Progress in electronic data processing systems points toward the storing of more information in smaller areas, quicker and more concurrent accessibility of information, and the expansion of shared data banks. Such rapid change requires that the facilitation of communication between data processing professionals and auditors be increased through training, that basic internal control principles which will remain unchanged be emphasized, that auditors accept more responsibility in the design and evaluation of data processing systems, and that 'on-line auditing' be expanded. 'On-line auditing' becomes increasingly important as after-the-fact auditing becomes more difficult. On-line auditing involves the implementation of special programmed controls recommended by the auditor. The controls are those which, if always operable, will assure the auditor that the system is continuously guarding against the processing of illegal transactions or incomplete or inaccurate data. Periodic audits of a computer-oriented system will be made much easier by use of the online auditing concept.