The microwave spectrum of CH3OD has been observed in the frequency region between 14 and 92 GHz. All the ground-state transitions with J ≤ 8 and J = 2 → 1, a-type transitions in the excited torsional states (ν = 1 and ν = 2) have been observed. The spectrum has been analyzed and rotational constants, torsional constants, torsion-vibration-rotation interaction constants, and centrifugal distortion constants have been evaluated. The Stark effect measurements have been made and the dipole moment components have been determined as μa = 0.833 ± 0.008 D and μb = 1.488 ± 0.015 D. Copyright © 1980 by Academic Press, Inc.