The effects of long-term (41 weeks) feeding of soybean phospholipid (SPL) on the level of serum cholesterol (chol) and immunological and physiological parameters were compared with those of soybean oil (SO). 1) Body weight gain was lower in SPL group when compared to SO group although food intake was similar between the groups. 2) The concentration of serum chol was significantly lower in SPL group. 3) Supplementation of SPL did not affect urinary proteins and pH, serum immunogloblins (IgG and IgM) and cutaneous delayed hypersensitivity. 4) It is concluded that hypocholesterolemic effect by SPL can be maintained for long-term period without any adverse effects on physiological functions.