Aim: The aim of this experimental work was to investigate the efficacy of Tc-99m-L-Cysteine (Cys) in scintigraphic visualization of inflammatory lesions in comparison to Tc-99m-L-glutamine (G), and (99)mTc-HIG. Methods: In mice abscesses were induced by intramuscular injection of turpentine. Six days later mice were injected with 3.7 MBq of each agent and sacrificed in groups of three at 1, 3, 6 and 24 h. Scintigrams were obtained with a gamma camera. The organs, some blood, abscesses, some muscle and urine were removed, weighed and counted in a gamma counter. Percentage of uptake by organs and per gram tissues and abscess/normal tissue concentration ratios were calculated. Experimental arthritis was produced in 6 New Zealand rabbits by intraarticular injection of ovalbumin. Four days later 37 MBq of Tc-99m-Cys and Tc-99m-HIG were each i.v. administered to 3 rabbits. Scintigrams obtained at 1, 3, 6, and 24 h demonstrated the arthritic joints very well. ROI's over arthritic joints were compared to contralateral normal joints (A/C). Results: In mice the abscesses were well visualized on all scintigrams. The maximum abscess/muscle ratios were 5.21 +/- 1.09 (6 h), 3.73 +/- 0.81 (3 h) and 5.98 +/- 1.17 (24 h) and the maximum abscess/blood ratios were 3.46 +/- 1.33 (24 h), 1.81 +/- 0.10 (6 h) and 0.914 +/- 0.351 (24 h) for Tc-99m-Cys, Tc-99m-G, and Tc-99m-HIG, respectively. In rabbits the maximum AIC ratios were 2.61 +/- 0.53 (3 h) and 2.92 +/- 0.99 (24 h) for Tc-99m-Cys and Tc-99m-HIG, respectively Conclusion: our results indicate that Tc-99m-Cys is a promising agent for imaging inflammatory lesions. It is preferred to Tc-99m-HIG, because of higher concentration ratios attained earlier, lower blood background, lower cost and a simpler in-house preparation method.