Authors analyse the value of the Holter system for diagnosis and follow-up of cardiac dysrhythmias. They report their experience from 100 records performed to 87 patients, who were between one day and 14 years old. Among them, 58 were male and 42 female. The recorder and analyser were automatics holter II/Quickscan, and the program was 24 hours in all cases. For the study of results, patients were divided in five groups (34 dysrhythmias; 18 neurologic; 10 were normal control; 20 newborns between 1 and 7 days; and 17 in a miscellaneous group). They emphasized on the possibility of the system to be performed in pediatric patients, even in the youngest; on the worth of records from neurologic with normal clinical examinations; on diagnostic aspects of undetected dysrhythmias by ECG (30%), and to know the normal values from the control group. Tables and figures show rhythm types and quantitative values; finally they comment on artifacts and indications.