Abstract: A number of novel antihemostatic peptides are claimed. Included among the antihemostatic peptides claimed are R-T-K-L-F-W-I-S-Y-S-D-G-D-Q, Y-S-D-G-D-Q-C, L-L-V-N-G-A-Q-L-C, C-F-D-K-I-K-N-W-R-N-L-I-A-V-L-G-E-H-D-L-S, F-D-K-I-K-N-W-R-N-L-I-A-V-L-G-E-H-D-L-S-E-H-D-G-D-E-Q-S-R-R-V-A-Q-V-I, L-G-E-H-D-L-S-E-H-D-G-D-E-Q-S-R-R-V-A-Q-V-I, A-V-L-G-E-H-D-L-S-E-H-D-G, V-R-F-S-L-V-S-G-W-G-Q, G-Q-L-L-D-R-G-A-T-A-L-E-L-M-V-L-N-V-P-R-L, A-G-Y-S-D-G-S-K-D-S-C, P-H-A-T-H-Y-R-G-T-W-Y-L-T-G-I and V-Y-T-R-V-S-Q-Y-I-E-W-L-Q-K-L and their analogues. The peptides are useful for inhibiting the formation of the Factor VII-tissue factor macromolecular complex of for inhibiting the activation of Factor X by Factor VII.