This study was performed to standardize the values of normal waves, complexes, and intervals of the electrocardiogram in clinically healthy feline neonates. Serial electrocardiography was performed in 15 female and 15 male neonates on the 1st through 9th days of life, then again on days 16, 21, and 30. The parameters analyzed were heart rate and rhythm, duration and amplitude of electrocardiographic waves, duration of intervals, and heart electrical axis. Non-parametric statistical analysis was used with Friedman, and Mann-Withney tests, for each of the appraised parameters. No significant statistical differences were observed between females and males for any of the analyzed parameters. During the neonates' first 30 days of life, migration of the electrical axis from right to left was observed. A sinus heart rhythm was predominant. There was a progressive increase in the R wave amplitude, while the S wave showed a progressive decrease. The neonatal parameters were within the normal patterns specified for adult cats.