Insulin resistance (IR) in horses is due to genetic factors, lack of exercise and over feeding. Clinical findings include obesity, abnormal fat deposits, lethargy, retention of hair and in advanced cases, laminitis. Conventional treatments with drugs and starvation diets do not work well in many cases. From a traditional Chinese veterinary medicine (TCVM) perspective, overfeeding results in accumulation of Internal Dampness and Heat that damages the Spleen. Additionally, many horses receive little regular exercise, which causes Stagnation and accumulation of Heat. Lethargy develops because insulin is unable to enter the cells to carry glucose for energy and Qi Deficiency results. Spleen Qi Deficiency with Damp Heat Accumulation is the most common TCVM pattern for IR in horses. The author uses a combination of Chinese herbal medicine (Jian Pi Ni Dang Tang) and nutritional supplements to improve insulin sensitivity in affected horses. Jian Pi Ni Dang Tang is a custom made formula related to the Spleen tonic, Jian Pi Wan and can be compounded as a powder or obtained in a concentrated granular form called Insulineze, from Natural Path Herbs. The author has also developed 2 nutritional formulas to improve insulin sensitivity, Harmany’s OB Formula and INR Formula for horses available from Advanced Biological Concepts, Osco IL. Jian Pi Ni Dang Tang along with diet and lifestyle changes may effectively treat IR in horses better than conventional treatments. Jian Pi Ni Dang Tang is administered for 3-6 months and repeated in the spring or fall during the seasons of rich grasses.