Plasma levels of homocysteine (Hcy), folic acid (FA) and Vitamin B12 (VB12) were measured in 120 patients of colon adenomatous polyps and 40 healthy subjects. Plasma Hcy levels in colon adenomatous polyps patients were significantly higher than those in controls[(14.24 ± 0.52) μmol/L vs.(10.93±0.81) μmol/L, P=0.0014)], while plasma FA levels in polyps patients were lower than those in controls [(6.26±0.27) μg/L vs.(10.74±0.85) μg/L, P<0.0001]. There was no difference in plasma VB12 levels between two groups(P=0.7100). The plasma Hcy levels in patients with multiple colon polyps were higher than those with single colon polyps(P=0.0092), while the plasma FA levels demonstrated contrary results (P=0.0047). With the pathological type progression, the plasma Hcy levels were gradually raised, and FA levels gradually decreased. Plasma levels of FA, Hcy and VB12 were not correlated with the location and distribution of polyps. These results suggest that plasma FA and Hcy levels may be related to disease progress in patients with colon adenomatous polyps. Key words: Adenomatous polyposis Coli; Homocysteine