We studied the effects of single intravenous injection of antibodies to brain-specific transmembrane anion transporter (BSAT1; 5 mg/kg) to pregnant rats (gestation day 10) on cognitive functions and behavior of their progeny. One of major functions of BSAT1 (or Oatp1c1) is specific transport of thyroxin across the blood-brain barrier. Female rats of two control groups were injected with non-specific Ig and 0.9% NaCl. The progeny of rats receiving monoclonal antibodies to BSAT1 demonstrated memory impairment in the Y-maze, novel object recognition test, passive avoidance test, and Morris water maze test in comparison with the control group. Our findings suggest that single injection of monoclonal antibodies to BSAT1 during the prenatal period was followed by cognitive impairments, which were probably related to thyroxin deficiency in the nervous tissue.