Place carrots in a pot with enough water to cover. Bring to a boil, covered & cook till tender. Drain, reserving 1/2 cup of liquid. Puree carrots & liquid. Transfer to large pot. Add rhubarb & sugar to pot & stir till sugar is dissolved. Bring to a slow boil & simmer gently for 20 minutes. Remove from heat & pour into warm sterile jars. Seal.