To determine if nuclear/cytoplasmic (N/C) gradients of ions exist in mammalian hepatocytes, as has been shown to exist in the amphibian oocyte, small pieces of mouse liver were cryofixed for energy dispersive X-ray microanalysis of Na, K and Cl in thin freeze-dried cryosections. Expressing the data on a dry weight basis showed small but significant N/C gradients for Na and K but not for Cl. When the data were expressed on a wet weight basis no significant N/C gradients of Na, K or Cl were revealed. Questions of data interpretation are discussed.