Recent studies report an interesting role of peroxisome proliferator-activated receptor (PPAR) antagonists in different tumor models, being these compounds able to perturb metabolism and viability in cancer cells. In this work, the identification of a novel PPAR antagonist, showing inhibitory activity on PPARα and a weaker antagonism on PPARγ, is described. The activity of this compound and of a series of chemical analogues was investigated in selected tumor cell lines, expressing both PPARα and PPARγ. Data obtained show a dose-dependent cytotoxic effect of the novel PPAR antagonist in colorectal and pancreatic cancer models.