ECGs of various carp recorded with bipolar leads from certain positions on the body surface showed almost the same patterns. ECGs reco rded from pectoral fins, left and right fins connected with the plus and the minus terminals of ECG apparatus respectively, exhibited the upward or diphasic P wave and the QS or Qr or QR type of QRS complexes and ECGs from lower jaw (minus terminal) and either anal or caudal fin (plus terminal) showed the upward or diphasic P wave and the R or QS type of QRS complexes. It can therefore be presumed that in the case of carp heart the excitation spread through the atrium from dorsal to ventral direction radially and through the ventricle both from left to right and from basis to the apex.