This paper describes the usage of a portable Surface Plasmon Resonance system for label free detection of DNA from Mycobacterium tuberculosis complex. A single-strand oligodeoxynucleotide, carrying a thiol end group (and also a spacer arm), which is complementary of the target characteristic sequence of Mycobacterium tuberculosis complex was used as the "probe" and immobilized onto the gold coated surfaces of the Surface Plasmon Resonance slides as Nano-overlayers by using a direct immobilization method based on the self-assembled over-layer formation. A modulator-spacer molecule 6-mercapto-1-hexanol was also co-immobilized in order to optimize the surface density of the probe-oligodeoxynucleotides and to orient them for better interaction. It is demonstrated that the reported Surface Plasmon Resonance biosensor platform can be used successfully to detect target molecules both synthetic and Polymerase Chain Reaction products very effectively at nM levels. The sensor platforms can also be regenerated with 2.5 mM HCl and reused effectively. It has been shown that developed biosensor has high specificity, sensitivity, sensor reproducibility and long shelf life for both small synthetic oligodeoxynucleotides and Polymerase Chain Reaction amplified real samples.