No data exist concerning the total sinoatrial conduction time (TSACT) in children that compare values determined by the atrial extrastimulation technique (TSACT S ) with those generated by the atrial pacing method (TSACT N ). In this study, TSACT in 55 patients, age 0.2–18.5, was measured using both techniques. TSACT N was performed at a mean 90% (TSACT N−90 ) ( n =32) or a mean 95% (TSACT N−95 and ( n =38) of sinus cycle length (SCL). When data generated during determination of TSACT N−90 and TSACT S were compared, SCL and recovery cycle length (REC) were similar for both techniques. Likewise, TSACT S (128±40 ms) and TSACT N−90 (126±74 ms) were not significantly different. Coefficient of correlation was r =0.82, p <0.001. Chi-square analysis demonstrated a strong association of normal and abnormal values between TSACT S and TSACT N−90 . In contrast, when values generated during TSACT N−95 and TSACT S were compared, TSACT S exceeded TSACT N−95 (137±38 vs 105±58 ms; p <0.001). Values for SCL and REC were similar while correlation between TSACT determined by the two techniques remained strong ( r =0.82, p <0.001). Despite a good correlation between TSACT N−90 and TSACT S , individual differences in magnitude and direction were noted between the two techniques.