Stored electrograms (EGMs), well-known diagnostic tools in implantable cardioverter defibrillators, have now been incorporated in pacemakers as well, thereby increasing their diagnostic capabilities. The clinician can detect and diagnose patient arrhythmias with EGMs and directly validate diagnostic data stored by the devices. The appropriateness of detection algorithms can also be judged. Initial experiences with pacemaker EGMs reveals their potential to detect and diagnose sensing or detection algorithm problems. These so-called "false-positive" EGMs help to optimize pacemaker programming. Date and time stamp can correlate an event to patient symptoms. Recent advances, like onset recordings and marker annotation, have further increased the effectiveness of stored EGMs. The use of patient-triggered magnet-stored EGMs facilitates diagnostic workups in symptomatic pacemaker patients and reveals nondevice related symptoms in a considerable number of cases. Stored EGMs in pacemakers will soon be a standard diagnostic tool that can illustrate what is really going on in our patients.