We associate a family of Hilbert spaces Hq2;(D) of analytic functions on the unit disk D=z
:|z|<1 the q-continuous Gegenbauer polynomials Cn(x;q) on the interval]–1;1 and give a q-analogue of the unitary integral transform that Watanabe constructed from the Hilbert space L2(]–1;1;(1–x2)–
dx onto the weighted Hilbert space H2;(D).