The microbiological information system ISM gives the possibility to collect data of patients and findings on punch strips, to transmit the findings to the senders and to store and evaluate the data according to medical points of view and for the purpose of performance statistics. The essential elements of the system are demonstrated and the basic principles of the data processing apparatus type R300 are described. Here the author particularly enters the calculator-internal testing processes for elimination of codation and punching errors. Finally the further development of the information system provided is briefly sketched. The advantages of the use of electronic data processing result from 1. the simplificstion and unification of the information relations, 2. the reduction of writing work, 3. the centralised transmission of findings, 4. the increased security of data and 5. the possibility of mathematico-statistical evaluations of the stored data material. According to its basic conception the information system ISM may be used universally and it is possible to enlarge it.