Kiwifruit is a subtropical fruit that is very popular among consumers. Kiwifruit 'Hayward' ( Actinidia deliciosa C.F. Liang et A.R. Ferguson) is an important source of bioactive compounds and possesses high antioxidant capacity, but its value can be changed during ripening. The aim of this study was to compare the levels of total polyphenols (TP), ascorbic acid (AA), and total antioxidant capacities (TACs) of ethylene-treated and nontreated kiwifruits 'Hayward' from conventional and organic farming. The influence of these fruits on lipid profile, TAC, and liver enzymes in plasma of rats fed diets with cholesterol was studied. Ethylene treatment shortened the ripening of kiwifruits. Ethylene-treated kiwifruits from organic farming (OHE) have the highest contents of TP and TAC. The experiment in vivo was performed during 33 days on male Wistar rats (111 ± 5 g), divided into six groups: one without cholesterol, control (C), and five groups with 1% of cholesterol (Chol). Four groups with cholesterol were supplemented with 5% of lyophilized kiwifruits: ethylene treated, organic (Chol/OHE) or conventional (Chol/CHE); and untreated, organic (Chol/OHC) or conventional (Chol/CHC). Cholesterol diets supplemented with kiwifruit influenced the palatability and feed intake, body gain, and FER. Diets containing kiwifruits significantly influenced the decrease of TG (61%), TC (29%), LDL-C (38%), atherogenic index TC/HDL-C (25%), and atherogenic index (AI, 32%), without differences between treatments. A significant increase of TAC in plasma of rats fed kiwifruit was obtained by DPPH (18%), FRAP (55%), and ABTS (55%). Aspartate aminotransferase (AST) activity in serum was significantly lower for all groups with kiwifruit supplementation. Alanine aminotransferase (ALT) was lower only in diet groups supplemented with conventional fruits in comparison with the cholesterol group. Glucose levels were higher in groups with kiwifruit supplementation than in C and Chol groups. Supplementation of Chol groups with organic kiwifruits influenced the prothrombin index and significantly decreased the amount of platelets (PLT) in blood. In conclusion, studied kiwifruit 'Hayward' can be a very good ingredient of the diet, especially for patients suffering from hypercholesterolemia and with other cardiovascular diseases, but not for diabetic patients.