We consider a symmetric minimal relation L 0 generated by an integral equation with operators measures. We describe the generalized resolvents of L 0 using the characteristic function M(λ) (λ ∈ C), i.e., a function that has the property (Imλ) −1 ImM(λ) ⩾ 0. We obtain a necessary and sufficient condition for a holomorphic function M(λ) to be a characteristic function of a generalized resolvent. We give a detailed example of finding the characteristic function.