A new and distinct cultivar of Chrysanthemum plant named `Yoottawa`, characterized by its uniform and outwardly spreading plant habit; strong and freely branching growth habit; dark green-colored foliage; uniform flowering response and habit; can be grown as a disbud or as a spray-type; early flowering habit; decorative-type inflorescences with elongated oblong-shaped ray florets; white-colored ray florets; and good postproduction longevity with plants maintaining good substance and color for about four to five weeks in an interior environment.