Aims: It is unknown whether cardiomyocyte hypertrophy and the transition to fatty acid oxidation as the main source of energy after birth is dependent on the maturation of the cardiomyocytes' metabolic system, or on the limitation of substrate availability before birth. This study aimed to investigate whether intrafetal administration of a PPAR agonist, rosiglitazone, during late gestation can stimulate the expression of factors regulating cardiac growth and metabolism in preparation for birth, and the consequences on cardiac contractility in the fetal sheep at ~140d gestation. Methods: The mRNA expression and protein abundance of key factors regulating growth and metabolism were quantified using qRT-PCR and Western blotting, respectively. Cardiac contractility was determined by measuring the Ca²⁺ sensitivity and maximum Ca²⁺ activated force of skinned cardiomyocyte bundles. Results: Rosiglitazone treated fetuses had a lower cardiac abundance of insulin signaling molecules, including IRβ, IRS-1, phospho-IRS-1(Tyr895), PI3K regulatory subunit p85, PI3K catalytic subunit p110α, phospho-PDPK-1(Ser241), Akt-1, phospho-Akt(ser273), PKC, phospho-PKC(Thr410), AS160, phospho-AS160(Thr642) and GLUT-4. Additionally, cardiac abundance of regulators of fatty acid β-oxidation, including AdipoR1, AMPKα, phospho-AMPKα(Thr172), phospho-ACC(Ser79), CPT-1 and PGC-1α was lower in the rosiglitazone treated group. Rosiglitazone administration also resulted in a decrease in cardiomyocyte size. Conclusions: Rosiglitazone administration in the late gestation sheep fetus resulted in a decreased abundance of factors regulating cardiac glucose uptake, fatty acid β-oxidation and cardiomyocyte size. These findings suggest that activation of PPAR using rosiglitazone does not promote the maturation of cardiomyocyte, rather, it may decrease cardiac metabolism and compromise cardiac health later in life.