The paper addresses the problem of determining an outer interval solution of the parametric eigenvalue problem A(p)x = λ x, A( p) ∈ R n×n for the general case where the matrix elements aij ( p) are continuous nonlinear functions of the parameter vector p, p belonging to the interval vector p. A method for computing an interval enclosure of each eigenpair (λµ, x (µ) ), µ = 1, …, n, is suggested for the case where λµ is a simple eigenvalue. It is based on the use of an affine interval approximation of aij( p) in p and reduces, essentially, to setting up and solving a real system of n or 2n incomplete quadratic equations for each real or complex eigenvalue, respectively.