The mycotoxin citrinin (CFN), a natural contaminant in foodstuffs and animal feeds, exerts cytotoxic and genotoxic effects on various mammalian cells. An earlier study by our group shows that CTN has cytotoxic effects on mouse embryonic stem cells and blastocysts, and is associated with defects in their subsequent development, both in vitro and in vivo. Here, we further investigate the effects of CTN on oocyte maturation, and subsequent pre- and postimplantation development in vitro and in vivo. CTN induced a significant reduction in the rate of oocyte maturation, fertilization, and in vitro embryo development. Treatment of oocytes with 5 I.LM CTN during in vitro maturation (IVM) led to increased resorption of postimplantation embryos, and decreased placental and fetal weight. Using an in vivo mouse model, we show that consumption of drinking water containing 5 LM CTN results in decreased oocyte maturation and in vitro fertilization, as well as Early embryonic developmental injury. To our knowledge, this is the first study investigating the impact of CTN on maturation of mouse oocytes, fertilization, and sequential embryonic development. (c) 2008 Elsevier Ireland Ltd. All rights reserved.