During instruction in basic cardiopulmonary resuscitation (CPR) skills, cardiac massage and mouth-to-mouth ventilation are applied without interruption for no longer than a few minutes. The aim of this study was to see if the quality of technique during the first 2 min of CPR reflects the resuscitators ability to perform CPR over a 15 min period. Assessments were done with a resuscitation mannequin from which recordings of several variables were made at 2, 5, 10, and 15 min after the start of CPR. 60 lay volunteers who had received CPR training were studied, and six variables that describe the quality of CPR technique were recorded and scored with a predefined scoring system. No deterioration in CPR skills was seen during 15 min. We conclude that the initial 2 min assessment reflects the resuscitators ability to perform CPR over a longer period.