The evolution of science and technology has been shifted towards nano science and technology as the demand and application of the nano technology is growing very rapidly. With respect to this, metal oxide nano materials play very important role in various applications. Titanium dioxide is one of the most important metal oxide nano materials, which is being broadly investigated because of its unique hydrophobic nature, photo catalytic, electrical and optical properties. These nanoparticles are prepared by different physical methods,chemical methods and biological methods. This review article is focussed on various synthesis methods empha- sising on biological methods because of their wide range of techniques availabilities. Various characterisation techniques for biologically synthesised nanoparticles are discussed. The characterization techniques performed are XRD, FESEM, AFM, PSA, EDX, TG-DTA, FTIR and UV- Visible for the study of crystal structure, mor- phology & size, surface properties, average particle size, elemental compositions, thermal properties, bond analysis and optical properties respectively. Applications of these nano particles are described in briefly such as solar cells, sensors, device fabrication, self-cleaning and environmental.