A primary objective of the present investigation was to determine the tissue distribution of styrene, styrene glycol, and more polar metabolites in mice at different times (0.5-5 h) after the intraperitoneal administration of styrene (3.3 mmol/kg). Another aim was to determine the dose dependence of the metabolite pattern of styrene in the different tissues. The dose range chosen was 1.1-4.9 mmol of styrene/kg administered intraperitoneally, and the time delay 2 h after dosing. The highest initial concentrations of unchanged styrene were found in adipose tissue, pancreas, liver, and brain. Styrene glycol reached its maximum concentration within 1 h in most tissues. The levels in the kidneys, lungs, pancreas, and liver far exceeded those in subcutaneous adipose tissue. Only in the liver and kidneys was a notable amount of styrene glycol conjugated. Polar metabolites occurred to a considerable extent in the liver, kidneys, lungs, and plasma. The concentration of unmetabolized styrene seemed to increase exponentially with the dose in subcutaneous adipose tissue, liver, kidneys, lungs, and brain. No tendency towards a decreased relative occurrence of styrene glycol was observed at higher doses. However, when the dose was increased, the more polar metabolites occurred at relatively lower levels in all tissues except brain.