The first human MR imaging results for the hepatobiliary contrast agent manganese(II)N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'-bis(phosphate) (MnDPDP) are reported. MnDPDP is a paramagnetic contrast agent specific for hepatobiliary imaging. An imaging study was performed to investigate the presence of contrast enhancement or facilitated visualization of normal structures. Twelve healthy subjects receiving MnDPDP at doses of 3, 10, or 15 mumol/kg were imaged after injection for approximately 30 minutes at 1-5-minute intervals. Transaxial abdominal images were obtained at 1.5 T in a single breath-hold interval of 21 seconds with use of a spin-echo pulse sequence (repetition time = 150 msec, echo time = 20 msec). Liver parenchyma enhancement was observed 1 minute after injection and persisted for at least 30 minutes. Clearance into the gallbladder was visualized within 15 minutes. Enhancement was dose-dependent; a dose of 10 mumol/kg produced a 75%-100% signal enhancement of the liver at 10 minutes after injection.