Two trials were conducted to study the effect of spraying or feeding lindane on tissue residues, blood chemistry and physiological response of male and female swine. Treatments were: (1) control, (2) animals sprayed at 6-week intervals with an 0.05% lindane solution, (3) lindane fed at a rate of 2 mg/kg or (4) fed at the rate of 40 mg/kg of body weight per day. Six animals per treatment were used in each trial, evenly divided by sex. Initial ages averaged 115 days in trial I and 106 days in trial II. The trials ended after the females farrowed their first litters. Blood and backfat samples were taken at 6-week intervals during the trials. Lindane was detectable in blood but too low to quantify except for pigs on the 40-mg treatment. Lindane residues were found in backfat samples from all groups, but average levels in the control and sprayed groups never exceeded 4 ppm. In the 2-mg group, backfat levels reached a peak (50 ppm) at the fourth sampling, declined slightly and then reached their highest level (82 ppm) in the slaughter sample. Residues in fat from pigs fed 40 mg of lindane were higher at all sampling times than were those in any other group, reaching a level of over 260 ppm after 27 to 33 weeks of feeding. Lindane determinations were made on brain, kidney, liver and muscle obtained at the end of the trials. Highest levels generally were found in the 40-mg group. Analysis for serum creatinine, cholesterol, protein, albumin, and alkaline and acid phosphatase showed few consistent changes due to lindane exposure. Cholesterol was higher (P < .01) on the 40-mg level and albumin tended to be lower. Plasma free amino acids were examined and only isoleucine was elevated (P < .05) in the 2-mg group, while taurine, tyrosine and ornithine were higher (P < .05) in the plasma from the 40-mg treatment.