1. Events in utero appear to have a significant role in the development of cardiovascular dysfunction in adulthood. In the present study, we evaluated the effects of prenatal exposure to zymosan, a non-infectious and non-bacterial agent capable of inducing inflammation, on mean systolic arterial pressure (MSAP) in rat offspring at 6-66 weeks of age. 2. Pregnant rats were divided into three groups: (i) a control group, administered 0.5 mL, i.p., saline on gestation Days 8, 10 and 12; (ii) a zymosan-treated group, given 2.37 mg/kg, i.p., zymosan on gestation Days 8, 10 and 12; and (iii) a pyrrolidine dithiocarbamate (PDTC) + zymosan-treated group, which was given 100 mg/kg, i.p., PDTC 1 h before zymosan. At 6, 16, 26, 36, 56 and 66 weeks of age, MSAP was determined in rat offspring from all three groups. Serum levels of tumour necrosis factor (TNF)-alpha were determined in dams, as well as in offspring at 24 and 56 weeks of age. In addition, protein levels of nuclear factor (NF)-kappa B (p65) in the myocardium and kidney of offspring were determined at 24 weeks of age. 3. The results showed that MSAP and NF-kappa B (p65) levels in the myocardium and kidney of offspring from the zymosan-treated group were increased significantly compared with control. This increase was inhibited by concomitant treatment with PDTC. Serum TNF-alpha levels in dams exposed to zymosan and in their offspring at 56 weeks of age (but not at 24 weeks of age) were significantly increased compared with levels in the control group. Following lipopolysaccharide treatment (1 mg/kg, i.p.) of adult rat offspring at 24 weeks of age, there was a further increase in serum TNF-alpha levels in offspring in the zymosan-treated group compared with the other two groups. 4. The findings of the present study suggest that non-bacterial inflammation during gestation can lead to hypertension in offspring and that NF-kappa B signalling may play a critical role in this process.