  We study Euclidean 3D N=2 supersymmetric gauge theories on squashed
three-spheres preserving isometries SU(2) x U(1) or U(1) x U(1). We show that,
when a suitable background U(1) gauge field is turned on, these squashed
spheres support charged Killing spinors and therefore N=2 supersymmetric gauge
theories. We present the Lagrangian and supersymmetry rules for general gauge
theories. The partition functions are computed using localization principle,
and are expressed as integrals over Coulomb branch. For the squashed sphere
with U(1) x U(1) isometry, its measure and integrand are identified with the
building blocks of structure constants in Liouville or Toda conformal field
theories with b \neq 1.
