The main aim of the present study has been to investigate the electrochemical behavior of, and oxide film formation on, the bulk amorphous Zr55Cu30Ni5Al10 alloy and the crystalline counterpart in simulated body fluid. Different analytical methods, e.g., polarization and electrochemical impedance measurements, were used to compare the results of the samples when exposed to, phosphate buffered saline (PBS), with or without the addition of protein (albumin). Moreover, the influence of pH on the corrosion behavior of the materials was also investigated. Pitting corrosion was observed to exist on both amorphous and crystalline samples after exposure to the PBS solution, but the passivity region was much smaller for the crystalline material. The addition of protein to the PBS solution improved passive behavior and led to higher pitting potential in the case of the crystalline samples, while the pitting corrosion potential decreased slightly in the case of the amorphous samples. Furthermore, a decrease in the pH level accelerates the dissolution rate of both materials when exposed to the PBS environment, however, in the presence of albumin the pitting corrosion potential increased in the case of both materials.