We studied the transport of glycylsarcosine by the brush-border membrane vesicles isolated from normal term human placentas. This dipeptide resisted hydrolysis by placental membrane vesicles and was transported intact into an osmotically responsive intravesicular space. The transport process was Na+-independent and probably occurred down a concentration gradient. Many peptides inhibited the transport of glycylsarcosine whereas amino acids had no effect. These results demonstrate, for the first time, the presence of a dipeptide transport system in the human placenta.