Abstract. Let K be a compact Lie group, endowed with a bi-invariant Riemannian metric, which we denote by κ. The complexification K C of K inherits a Kähler structure having twice the kinetic energy of the metric as its potential; let ε denote the symplectic volume form. Left and right translation turn the Hilbert space HL 2 (K C , e −κ/t ηε) of square-integrable holomorphic functions on K C relative to a suitable measure written as e −κ/t ηε into a unitary (K × K)-representation; here η is an additional term coming from the metaplectic correction, and t > 0 is a real parameter. In the physical interpretation, this parameter amounts to Planck 's constant .We establish the statement of the Peter-Weyl theorem for the Hilbert space HL 2 (K C , e −κ/t ηε) to the effect that (i) HL 2 (K C , e −κ/t ηε) contains the vector space of representative functions on K C as a dense subspace and that (ii) the assignment to a holomorphic function of its Fourier coefficients yields an isomorphism of Hilbert algebras from the convolution algebra HL 2 (K C , e −κ/t ηε) onto an algebra of the kind b ⊕End(V ). Here V ranges over the irreducible rational representations of K C and b ⊕ refers to a suitable completion of the direct sum algebra ⊕End(V ).Consequences are: (i) the existence of a uniquely determined unitary isomorphism between L 2 (K, dx) (where dx refers to Haar measure on K) and the Hilbert space HL 2 (K C , e −κ/t ηε), and (ii) a proof that this isomorphism coincides with the Blattner-Kostant-Sternberg pairing map from L 2 (K, dx) to HL 2 (K C , e −κ/t ηε), multiplied by (4πt) − dim(K)/4 . Among our crucial tools is Kirillov's character formula. Our methods are geometric, rely on the orbit method, and are independent of heat kernel harmonic analysis, which is used by B. C. Hall to obtain many of these results