Serum lactoferrin level, using competitive enzyme linked immunosorbent assay (ELISA) method, was estimated in 298 leprosy patients admitted into the hospital and attending the out-patient department of the Schieffelin Leprosy Research and Training Center. Serum from an equal number of non-leprosy individuals served as control. Mean (SD) of serum lactoferrin in non-leprosy individuals was 0.277 (0-092) microg/ml while in leprosy patients it was 0.494 (0.394) microg/ml, the difference being significant (P=0.0001). Serum lactoferrin levels were not significantly associated with type 2 reactions (P=0.613). Serum lactoferrin was significantly associated with age (P = 0.006), duration of the disease (P=0.0001), DDS monotherapy (P =0.007), deformity (P= 0.005), average bacterial index (BI) (P=0.01) and smear positivity (P=0.0001), orbicularis oculi weakness (P= 0.001), lagophthalmos (P = 0.002), corneal opacity (P = 0.001) and cataract (P=0.004) in simple regression analysis. All these variables, with the exception of smear positivity (P=0.019), lost their significance (P>0.05) when analysed using multiple regression. Serum lactoferrin showed poor association with type 1 (P = 0.286) and type II reactions (P = 0.613) and iridocyclitis (P = 0.207). We conclude that serum lactoferrin is strongly and inversely associated with increasing BI but does not show significant association with type 2 reactions.