Second‐order differential pencils L(p,q,h0,h1,H0,H1) on a finite interval with spectral parameter dependent boundary conditions are considered. We prove the following: (i) a set of values of eigenfunctions at the mid‐point of the interval [0,π] and one full spectrum suffice to determine differential pencils L(p,q,h0,h1,H0,H1); and (ii) some information on eigenfunctions at some an internal point bMathClass-rel∈(π2MathClass-punc,π) and parts of two spectra suffice to determine differential pencils L(p,q,h0,h1,H0,H1). Copyright © 2013 The Authors. Mathematical Methods in the Applied Sciences published by John Wiley & Sons, Ltd.