The present investigations were performed to assess the differences among rat colonies commonly used for neurophysiological research regarding the development of complete Freund’s adjuvant (CFA)-induced arthritis. Inflammatory signs including edema in the paw fluctuated remarkably among individual Wistar (Slc/Wistar/ST) and Sprague-Dawley (Slc/SD) rats, while the inflammatory signs of Lewis (LEW/Crj) rats appeared earlier and was severer and more consistent than Slc/Wistar/ST and Slc/SD rats. Edema in the hind paw developed in 100% of LEW/Crj rats with the lowest dose of CFA (0.6 mg/rat) used as compared with 64% of Slc/Wistar/ST (CFA 1 mg/rat) and 38% of Slc/SD rats (CFA 1.2 mg/rat). Retardation of weight gain was observed in Slc/Wistar/ST and Slc/SD rats in contrast to a severe weight decrease in inflamed LEW/Crj rats after the development of arthritis.