This study was designed to evaluate the effect of 99mTechnetium-dicarboxypropane diphosphonate (99mTc-DPD) and 99mTechnetium-methylene diphosphonate (99mTc-MDP) on bone scan image quality and time in dogs with osteoarthritis. The left cranial cruciate ligament (CrCL) in ten healthy adult Beagle dogs was transected under general anesthesia. The dogs were assigned to 99mTc-DPD-injected or 99mTc-MDP-injected groups. Stifle joint scintigraphy was performed after intravenous injection of 10 mCi 99mTc-DPD or 99mTe-MDP. Scintigraphy was conducted before CrCL transection and 2, 4, 6, 8, 10 and 12 weeks after the procedure. There were no significant differences in density, sensitivity and pathological foci between the 99mTc-DPD and 99mTc-MDP groups of experimentally-transected CrCL dogs. A comparison of the images obtained with Pinhole type and low energy general purpose type collimators of the stifle joint of normal dogs and after CrCL transaction revealed no significant differences in bone radioactivity. Scintigraphs were obtained 3 h after 99mTc-MDP and 2 h after 99mTc-DPD injection. In conclusion, application of 99mTc-DPD and 99mTc-MDP in experimentally-induced osteoarthritis of the stifle joint in dogs results in similar effects on radioactive uptake ratio and image quality. 99mTc-DPD is more efficient than 99mTc-MDP in reducing the overall time of scintigraphy.