The?orientation?dependence of the?Raman?spectral features of individual protein/biomolecules?is studied using?surface-enhanced?Ramanscattering (SERS). Large variation in spectral features mainly in term of peak intensity is observed from small proteins/peptides. We aim to address the question of whether the spectral features of SERS are uniquely determined by the type of protein/molecules or are influenced prominently by factors more than the identity of the molecules such as?orientation?of molecules relative to the substrate?surface. The standard deviation in the intensity of individual?Raman?peaks diminishes for protein size larger than 13 amino acids. Secondary structure of protein (such as protein-protein interaction) remains unchanged regardless of protein?orientation. Numerical simulation studies corroborate the experimental observation in that the SERS spectral features of biomedically relevant protein (of larger than 13 amino acids in size, which represent all human protein types) are not affected by the?orientation?of amino acids randomly dispersed on SERS-active surfaces. These findings are instrumental to understanding the exceedingly high (label-free)?specificity?when SERS is used in identifying proteins/peptides as can be found in numerous publications from different research groups in both in vivo and in vitro analyses. It was noted that the spectral position of all?Raman?peaks assignable to the various amino acids are independent of molecule?orientation?even though their intensities do vary.