We improve the theoretical predictions for the production of extra neutral gauge bosons at hadron colliders, which are currently based on the leading order Monte Carlo generator PYTHIA, by implementing the Z' bosons in the MC@NLO generator and by computing their differential and total cross sections in joint p_T and threshold resummation. The two improved predictions are found to be in excellent agreement with each other for mass spectra, p_T spectra, and total cross sections, while the PYTHIA parton and ``power'' shower predictions show significant shortcomings both in normalization and shape. The theoretical uncertainties from scale and parton density variations are found to be 9 and 2%, respectively, and thus under good control. The implementation of our improved predictions in terms of the new MC@NLO generator or resummed K factors in the analysis chains of the Tevatron and LHC experiments should be straightforward and lead to more precise determinations or limits of the Z' boson masses and/or couplings.