Abstract.  Successful deposition of nano phase TiO₂ thin films on silicon and glass substrates were achieved using the dense plasma focus (DPF) device. TiO₂ thin films were prepared from a 99.95% pure titanium rod in oxygen–argon working gas mixture at ambient room temperature. The EDX and XPS results give the elemental composition of the films as Ti and O₂. The XRD shows that amorphous films are predominant for low number of plasma focus shots. The SEM micrographs confirm the presence of nano-sized grains at smaller number of deposition shots or higher distance of deposition. Agglomeration was found to increase with the number of deposition shots. On annealing, the XRD diffractograms exhibit an increased in intensity and line width of the anatase (101) with the rutile phase R (110) emerging above 400°C. UV-Vis absorbance spectra for both as deposited and annealed films show a red shift for depositions from 20 plasma focus shots. The films showed visible light catalytic activity through decolouration of methylene blue solution. Visible light activity reached a maximum and decreased after 600 °C. Red shift and visible light catalysis can be explained in terms of the special feature effects of the plasma focus characteristic emissions.