Abstract: Objective To evaluate the diagnostic efficacy o f Tc 99m -MDP bone scintigraphy in diabetic foot. Methods Tc 99m -MDP three-phase bone imaging was performed on 45 cases with di abetic foot and 36 controls without diabetes mellitus.Each foot was analyzed in dependently. Radioactive concentration per pixel(C,counts/pixel) was calculate d and the time-radioactivity curve of each region of interest (ROI) was created .The ratio of foot to tibia(R m/t ) was calculated.From the curve of perfu sion time (Tp) was read out and the uptake velocity(V)of foot was calculated. The indices such as R m/t ,Tp and V were compared between two groups.The di agnostic indices such as sensitivity,specificity,accuracy,positive prediction va lue and negative prediction value were calculated and compared. Result s In control group,the Tp,V and R m/t were (33±9)s, (2.3±0.8)c ounts/s and 0.85±0.29,respectively; in diabetic foot group, the Tp,V and R m/t were (36±13)s, (1.5±0.3)counts/s and 0.72±0.31,respectively.Tp s howed no significant difference (P>0.05), but V (P<0.001)and R m/t (P<0.01) showed significant difference when compared between the two gro ups. The sensitivity,specificity, and accuracy were 82.6%,83.8% and 83.3%,r espectively for the V value, and 65.2%, 68.8% and 67.3%,respectively for th e ratio of R m/t . The sensitivity(P<0.05) and specificity(P<0.05 ) of V value surpassed those of R m/t . Conclusions Tc 99m -MDP three-phase bone imaging can find the decreased uptake velocity (V)and foot-tibia ratio in diabetic foot.The uptake velocity is more sensiti ve and special than the foot-tibia ratio in the diagnosis.