The aim of the present study was to investigate the CGRP-IR pattern in the ureter in stone-implanted rats and ureteral formalin irritated rats. Artificial ureteral stone rats were made according to Giamberardino's guide lines. For urethral formalin irritated rats, a small amount of diluted formalin was instilled into the ureter. The behavioral characteristics were observed and recorded with CCTV and analyzed, statistically. The rats showing characteristic visceral episode were sacrificed three days after stone implantation operation and after overnight chemical irritation followed by immunostaining of the ureter with anti-CGRP on the ureter In the artificial ureteral stone rats, CGRP IR fiber pattern showed variable changes on the upper portion of the stone implanted ureter. i.e., complete depletion, reticular pattern, and reticular pattern with more increased CGRP immunoreactivity were observed. In contrast, more-distinct CGRP IR fibers formed a reticular pattern but were not increased in density in the formalin irritated ureter. The results show the variable changing pattern of CGRP immunoreactivity in the ureter after artificial urethral calculosis, and the constant CGRP immunoreactivity in the ureter after chemical ureteral irritation.