Background: Numerous studies have shown that Vegan diet has beneficial effects on the prevention of cardiovascular diseases. However, the effects of vegan diet on lipid profile and the association between duration of vegan diet and lipid profile, are still unclear. Objectives: The present study aims to investigate the prevalence and influence of a long period of attachment to a vegandiet on lipid profile. Materials and Methods: 144 Buddhist nuns aged 20-75 years with duration of vegan diet ranged 10-70 years, were screened for lipid disorders. They were compared with 68 age-matched women of aged 22-84 years on non-vegan diet. The lipid profile were assessed, including plasma concentration of TC, LDL.C, HDL.C, TG, and non-HDL.C. Results: The mean TC in vegan group was significantly lower than that in control group (4.8 ±1.11 vs 5.31±1.32 mmol/l, p <
0.05). The proportion of TG ( ≥ 1.7 mmol/l) in Vegan group was significantly lower than that in control group (43.8% vs 63.2%, p <
0.05). The proportion of LDL.C (≥ 3.4 mmol/L) in Vegan group was significantly lower than in control group (20.1% vs 41.1. p <
0.05). The average HDL.C in Vegan group was significantly lower than in control group (1.2 ± 0.2 vs 1.35 ± 0.39 mmol/l, p <
0.05). The proportion of HDL-C (<
1.3 mmol/L) in Vegan group was significantly higher than in control group (60.4 % vs 45.59%, p <
0.05). The mean non-HDL.C in Vegan group was significantly lower than in the control group (3.6 ± 1.00 vs 3.97 ± 1.20 mmol/l, p <
0.05). The proportion of non-HDL.C (≥ 3.4 mmol/L) in Vegan group was significantly lower than in control group (50.7% vs 67.65 % p <
0.05). Benefits of Vegan diet with respect to the prevalence of dyslipidemia were studied by using the ROC curves for predicting the age cut-off points between Vegan group and control group to
TC (61 vs 44 years), LDL.C (62 vs 44 years), non-HDL.C (46 vs 35 years) and TG (43 vs 53 years). The relationship between long-term vegan diet and dyslipidemia in vegan group. Dyslipidemia: TC was 29 yrs, TG was 27 yrs, decreased HDL.C was 27 yrs, increased LDL.C was 44 yrs There were correlations between duration of vegan diet and lipid profile (r = 0.307 - 0.525). Conclusions: A decrease in multiple lipid profile such as TG, LDL.C, non-HDL.C, was associated with vegan diet in female subjects. However, a long-term vegan diet could decrease HDL.C in this population