Transitions following the EC-capture decay of 4.4-day Np 234 have been investigated with 99-, 160- and 350-gauss permanent magnets, a solenoidal “long lens” spectrometer, and NaI(Tl) scintillation detectors with a 100-channel analyzer. Many internal conversion electron lines were observed, and assigned to transitions at 43.49, 99.70, 233.6, 234.6, 238.6, 247.9, 297.6, 450.5, 482.8, 485.1, 515.7, 525.9, 556.8, 744.1, 751.7, 767.9, 787.8, 793.8, 810.0, 812, 854, 1003, 1105, 1196, 1240, 1395, 1439, 1531, 1562, 1575 and 1606 keV. A few other weak electron lines were observed, but not assigned to transitions. Transitions following Np 236, Np 238, and Np 239 decay were also observed on the same plates and identified, helping to insure correctness of the isotopic assignment of the U 234 transitions. The above transitions have been interpreted to establish levels in U 234 at 43.49, 143.2, 788, 812, 854, 1049, 1090, 1092, 1240, 1340, 1439, 1575 and 1606 keV. The 812-keV E0 transition has been resolved into two components, one of which is interpreted to be an E0-transition between two 2 + states. Transition multipolarities and possible level spin and parity assignments are discussed. A comparison of the known data on relative energies of vibrational states indicates that the β-vibrational states have lower energies than the γ-vibrational states in the few nuclei where the energies of both are known.