Urea was successfully synthesized by illuminating size-quantized TiO2 nanocrystals (Q-TiO2) immobilized in polyvinylpyrrolidinone gel film in CO2-saturated propylene carbonate containing NO3 -and 2-propanol, the latter of which served as a hole scavenger. Commercially available TiO2 (Degussa P-25) also showed activities for the urea photosynthesis, though the production rate of urea was lower. The use of HCOOH or CO in place of CO2 also yielded urea. The same was true for the replacement of the nitrogen source from NO3 -to NH2OH or NO. The urea production was accompanied by production of other reduction products such as NH4 + and methanol, but their amounts were largely influenced by the kind of reaction substrates used. The sum of quantum efficiencies obtained for the reduction products showed good accordance with the quantum efficiency obtained for the sole oxidation product of acetone.