The present study explores the microstructural characteristics and electrochemical responses of different TiMoZrTa alloys designed for biomedical implantation. The alloys corrosion resistance (potentiodynamic polarization and electrochemical impedance spectroscopy) was determined in acidified Ringer's solution at 37 °C. The pH was adjusted to 3.6 in order to reproduce the pathological state. The new materials formed spontaneously a passivation oxide film on their surface, and they remained stable for polarizations up to +1.0 VSCE. No evidence of localized breakdown of the oxide layers was registered even when higher positive polarizations than those encountered in the human body were applied.