If

are two noises (stochastic processes),

and

are functions describing the action of two instantaneous nonlinear devices, we say that the

cross-correlation property holds in case the cross-correlation of

with

is proportional to the cross-correlation of

with

, whenever

and

are polynomials of degrees not exceeding

and

, respectively. We take

or

to mean that

or

is any continuous function. The Barrett-Lampard expansion

of the second-order joint density of

and

is used to derive an expression for the cross-correlation of

and

. This expression yields necessary and sufficient conditions for the validity of the cross-correlation property in three cases:

and

stationary,

unrestricted;

stationary,

unrestricted;

stationary,

. Examples are constructed with the help of special orthonormal polynomials illustrating the necessity and sufficiency of the conditions.