Dibromoacetic acid (DBA), a byproduct of water disinfection, has been shown to have adverse reproductive effects in male rodents. In light of the lack of data on potential effects on female reproduction, studies were initiated to evaluate the potential effect of the chemical on early pregnancy. Groups of mature Holtzman rats were used, and cycles were monitored in all animals by vaginal smears. The administration of DBA at 0, 62.5, 125, or 250 mg/kg/d to rats during the first 8 d of pregnancy had no effect on the number of implantation sites found on Day 9 nor any other progestational parameter, except for serum estradiol, which was elevated. When groups of pregnant rats treated with the same range of dosages of DBA during Days 1 through 8 of pregnancy were killed on Day 20, there was no effect of treatment on the number of pups/litter, number of resorptions, or mean pup weight. These data demonstrate that while DBA has serious adverse effects on reproduction in male rodents, the chemical does not affect early pregnancy in rats. Effects on ovarian function and latent fertility are not ruled out.