We measured voluntary water and sodium intakes of 40 inbred strains of mice. Groups of approximately 10 males and approximately 10 females from each strain received a series of 48-h tests with a choice between a bottle of water and a bottle of one of the following: water, 25, 75, and 225 mM NaCl, 25, 75, and 225 sodium lactate. Sodium solution intakes were influenced by strain, sex, anion and concentration: Nine strains drank significantly more chloride than lactate, and only one strain (I/LnJ) drank significantly more lactate than chloride. The other 30 strains drank similar volumes of chloride and lactate. Sodium intakes were higher in females than males of 8 strains and did not differ by sex in the other 32 strains. Some strains had consistently high sodium intakes and preferred all sodium solutions to water (129S1/SvImJ, MA/MyJ, NZW/LacJ and SWR/J), some showed indifference (i.e. preferences not significantly different from 50%) to all concentrations tested (A/J, C57BL/6J, FVB/NJ and SEA/GnJ), and some had consistently low sodium intakes (AKR/J, C3H/HeJ, C57BL/10J, CBA/J, DBA/2J, I/LnJ, JF1/Ms, LP/J, NON/LtJ, PERA/EiJ, PL/J, and RIIIS/J). The results illustrate the diversity of voluntary sodium intake in mice and will assist in the selection of appropriate strains for focused genetic and physiological analyses.