Mass yield distribution in the epi-cadmium neutron-induced fission of 237Np has been carried out by measuring the cumulative yields of fission products within the mass ranges of 78 to 117 and 123 to 157. A radiochemical and off-line gamma-ray spectrometric technique was used for the measurement. From the cumulative yields of the fission products, mass chain yields were obtained by applying the charge distribution correction. Mass yield distribution parameters such as the full-width at tenth-maximum of light and heavy mass wings, the peak-to-valley (P/V) ratio, and the average light mass <AL> and heavy mass (<AH>) as well as the average number of neutrons <ν> were obtained. The mass yield data in the epi-cadmium neutron-induced fission of 237Np were compared with the similar data in thermal and 14.5- to 14.7-MeV neutrons to examine the role of excitation energy in nuclear structure effect and P/V ratio.