Constructive empiricists claim to offer a reconstruction of the aim and practice of science without adopting all the metaphysical commitments of scientific realism. Deflationists about truth boast of the ability to offer a full account of the nature of truth without adopting the metaphysical commitments accompanying substantive accounts. Though the two views would form an attractive package, I argue that the pairing is not possible: constructive empiricism requires a substantive account of truth. I articulate what sort of account of truth and empirical adequacy the constructive empiricist must offer and then show why deflationists cannot uphold such an account.