Optical properties of gold nanoshell-based contrast agents for optical coherence tomography (OCT) were determined using calculations based on concentric sphere Mie scattering theory. Nanoshells capable of optimal optical scattering in the near infrared (NIR) were subsequently fabricated. We show that scattering nanoshell possess higher backscattering efficiencies at longer wavelengths. Results show enhanced OCT signal intensities after addition of gold nanoshells to scattering tissue phantoms. In addition, in vivo mouse tumor model studies show clear evidence of enhancement of tumor scatter after nanoshell injection as compared to control (Phosphate Buffered Saline, PBS) injections, further demonstrating the potential of gold nanoshells as NIR contrast agents to improve scattering-based optical imaging technologies. In addition to the data shown in this preliminary paper, the talk will present more recent data using immunotargeted nanoshells for molecular contrast OCT.