The effects of the amount of water hydrated in N-methylmorpholine N-oxide (NMMO) in dry jet-wet spinning of cellulose was investigated in terms of rheological properties of the spinning dope and the physical properties of the fiber. At the identical polymer concentration of 12 wt%, the solution of cellulose in 90.4 wt% NMMO gave higher viscosity and higher storage modulus (G') than that in 86.7 wt% NMMO, which was more noticeable at 110℃ than at 120℃. Decrease in the hydrated water level or increase in the air-gap or spin draw ratio increased such physical properties of the fiber as birefringence, initial modulus and tensile strength. The tensile fractured morphology revealed that the fiber from NMMO containing less water gave more fibrils resulting from higher orientation. Further, it produced thicker and longer fibrils when treated with an ultrasonic generator.