This study evaluated the tensile properties of oblique partial tendon lacerations and the effects of peripheral sutures on their strength. Seventy-four fresh pig flexor digitorum profundus tendons were divided into eight groups and were transected across 90% of their diameter. The lacerations in the tendons of five of the groups were at 0 degrees, 15 degrees, 30 degrees, 45 degrees, and 60 degrees to their transverse cross-section, respectively. In the other three groups the lacerations were 0 degrees, 45 degrees, and 60 degrees to the cross-section and were repaired with running peripheral sutures. The tendons were subjected to load-to-failure tests in a tensile testing machine to determine the initial, 1 and 2mm gap formation forces, and the ultimate strength. Obliquity of tendon lacerations affected the strength of partially lacerated tendons. The tendons with 45 degrees and 60 degrees oblique lacerations had a significantly lower ultimate strengths than those with transverse (0 degrees), or 15 degrees or 30 degrees oblique lacerations. Running peripheral sutures significantly increased both the gap formation forces and the ultimate strength of the tendons with oblique partial lacerations.