The object of the study is the hearts of four young reproductivefemales of the Amur leopard cat, a rare mammal representativeof the cat family. The animal is untamed and lives only in thewild. The material was selected during the autopsy according togenerally accepted methods. The age of the studied individualsof the Amur leopard cat was determined taking into account thedata; the internal structure features of the heart were studied.Earlier, we described the morphometric parameters of differentage groups male hearts. The heart of the studied individuals isslender, ellipsoid in shape; the myoendocardial formations of theatria have a well-defined ridge-like structure. The walls of theventricles are characterized by pronounced trabeculation. Thepapillary and trabecular complex includes: trabeculae carneaeof varying intensity, depending on the localization on the wall;septomarginal trabeculae that have their own distinctive featuresin the right and left ventricles; main and additional papillary muscles.The septomarginal trabeculae of the right ventricle have apronounced muscular structure; the corresponding formationsof the left ventricle are thin, tendon-like, significantly exceedingthe first in length. The most pronounced papillary muscles are localizedin the left ventricle. Papillary muscles of the right ventricleare expressed slightly, with the exception of the parietal muscles.