The aim of this study was to evaluate whether change in the patients' position during the electrocardiogram (ECG) recording alters the various components of the ECG curve. Concerns whether ECGs in medically compromised patients recorded in a sitting position should be considered "standard" tracings and whether ECGs recorded in the supine and standing positions and ECGs recorded in different positions in the Exercise Laboratory are interchangeable provided the impetus for this study. The ECG was recorded in the supine and standing positions in 10 patients using standard electrode placement and in the sitting, standing, and supine positions in 16 patients using the Mason-Likar electrode system. Comparisons of sums of P waves and QRS complexes of various combinations of ECG leads from recordings in different positions and amplitudes of Q, R, and S waves of all 12 ECG leads revealed stability in the standard and stress ECGs, although few statistically significant but minor changes were noted in some comparisons, which, however, could not be expected to have any diagnostic significance. Comparison of standard ECGs recorded in patients in the supine and standing positions and stress ECGs recorded in the sitting, standing, and supine positions are interchangeable; this should allay concerns about recording the standard ECG in unconventional positions and may facilitate and make more cost-effective ECG recording in busy outpatient clinic environments.