Since cyclooxygenase (COX) inhibitors have been pointed out as potential treatments to increase pregnancy rates after embryo transfer, the present experiment aimed to evaluate the effects of flunixin meglumine (FM) and parecoxib (P), a COX-1 and 2 or COX-2 specific inhibitor, respectively, on the development of bovine embryos until the hatched blastocyst stage. In vitro produced bovine embryos were cultured in media with different concentrations of FM (0.14; 1.4; 14; 140 or 1400 µg/ml) or P (0.09; 0.9; 9; 90 or 900 µg/ml) and the production rates were evaluated. Concentrations of FM ≤14 µg/ml and P ≤90 µg/ml did not impair embryo development, although compiled data from non-lethal FM concentrations (≤14 µg/ml) indicated a toxic effect enough to decrease the hatching rate of blastocysts. Concentrations of FM at 140 and 1400 µg/ml and P at 900 µg/ml were lethal as no cleavage was detected on presumptive zygotes.