Optimization of in vitro oocyte maturation conditions is crucial to maximize the number and quality of the transferable embryos. A demand for optimised chemically defined, serum-free medium for this purpose is increasing. Polyunsaturated fatty acids (PUFAs) have been shown to influence oocyte competence. Many ruminant diets are rich in the omega 6 Linoleic acid (LA) which has detrimental effect on oocyte developmental competence in vitro in the absence of antioxidants. In ruminants, biohydrogenation of fatty acids changes the structure of a high proportion of dietary LA into conjugated LA (CLA). The aim of this study was to compare the effect of LA and CLA supplementation to serum‑free maturation media on the oocyte maturation rate and subsequent embryo development. The result revealed that the cumulus cell expansion and oocyte nuclear maturation to MII stage were inhibited by LA supplementation. This was reflected in subsequent development where higher proportion of embryos produced from the LA-treated oocytes were blocked at 2–cell stage and resulted in lower cleavage and blastocyst rates. The quality of the blastocyst produced in the LA group was similar to that of the control. In contrast, CLA did not affect cumulus cell expansion, nuclear maturation or the subsequent cleavage and blastocyst rates, however, blastocysts produced form CLA-treated oocytes had more total cell numbers due to increased trophectoderm (TE) cells. In conclusion, in serum free conditions, CLA supplementation resulted better quality embryos when compared to LA.