In this study, the effects of the praseodymium doping and calcination temperature for titania based catalysts synthesized using a sol-gel method on the photocatalytic methylene blue degradation reaction were investigated. Doping TiO2 with 1% Pr stabilizes the anatase crystal structure by inhibiting anatase to rutile transformation, increases surface area, and light absorption capability . Besides the Pr doping, effect of calcination temperature on the methylene blue degradation was investigated both with powder and thin-film catalysts. Experimental results showed that catalysts calcined at 600 degrees C had higher photocatalytic activity than the ones calcined at 500 degrees C. Moreover, Pr doping was also observed to enhance the photocatalytic performance of powder samples, and complete conversion of methylene blue was achieved over the praseodymium doped titania powder catalysts. Dimerization of methylene blue molecules also effects the degradation rates and it was observed that dimer to monomer transition is faster on Pr doped catalysts.