It has been previously demonstrated that dietary glycine supplementation reverses vascular dysfunction in protein-restricted pregnant rat dams (Brawley et al., 2004) and lowers blood pressure in their offspring (Jackson et al., 2002). Due to the low sulphur content of casein, these diets were supplemented with methionine. The aim of this study was to investigate the effects of reducing dietary methionine in the low-protein diet during pregnancy on both the pregnant dams and their offspring. Three groups of female Wistar rats (n=6) were fed diets of either 18% protein with 0.5% methionine (control: C), 9% protein with 0.5% methionine (protein-restricted: PR) or 9% protein with 0.25% methionine (protein-restricted, low methionine: PR-lowMet) from conception. Food intake and weight gain were measured in the dams. Systolic blood pressure (SBP) and heart rate (HR) were measured using tail cuff in male (n=11-12) and female (n=10-11) offspring at day 28 and 112. Data are presented as mean ± SEM and differences calculated by one-way ANOVA with Bonferroni post-hoc correction for multiple analyses. Significance was accepted for p<0.05. During pregnancy, average daily food intake of the mother was significantly greater for PR-lowMet than PR dams (p<0.05) and C dams (p<0.01). The PR-lowMet dams also had a greater number of offspring per litter than PR dams (n= 13.0 ± 0.37 versus n= 10.3 ± 0.81) and gained more weight during pregnancy (p<0.05). There was no significant effect on the sex ratio of the offspring. In this study, protein-restriction did not have a significant effect on either SBP or HR in the male or female offspring, despite evidence of vascular endothelial dysfunction (Torrens et al, this meeting). Reduction of dietary methionine in the low-protein diet during pregnancy lowered SBP in the female offspring at 28 days (p<0.05) (C= 110.9 ± 9.7 mmHg: PR= 120.3 ± 4.7 mmHg: PR-lowMet= 92.4 ± 6.8 mmHg) and there was no effect at 112 days or in the males at either age. There is a close relationship between the metabolism of glycine and methionine and a methionine load can result in competition for glycine (Meakins et al., 1998). It appears that a diet which is lower in methionine than has previously been used for low-protein studies is more palatable and this may affect pregnancy outcome. However, lowering methionine produced a transient reduction in SBP only in female pups post-weaning. We do not find evidence of longer-term detrimental effects on offspring.