The objective of the present work is to contribute in understanding TiO 2 nanoparticles production in turbulent spray flames. Multiple in situ diagnostics from combustion research are employed to study the main processes that characterize the spray flame synthesis. In this way, the liquid break-up, the reactive flow and the TiO 2 particles production are analyzed using shadowgraphy, light scattering, global flame luminosity and OH* chemiluminescence techniques. Measurements showed that it is possible to simultaneously localize by shadowgraphy the spray, the nanoparticles and the hot/cold layer of the flow. Light scattering measurements allow to characterize the TiO 2 nanoparticles distribution in the flame central plane. Spontaneous global emission and OH* chemiluminescence results show quite different reactive flow patterns for liquid with and without TTIP. When TTIP injection is considered, the liquid is localized in a small region close to the injector nozzle where it is dispersed by the oxygen flow resulting in droplets. The liquid droplets rapidly evaporate and TTIP is quasi-immediately converted to TiO 2 nanoparticles. Results show high interactions between nanoparticles and the turbulent eddies. These results illustrate the high potential of in situ optical diagnostics from combustion research to improve the knowledge on flame synthesis of nanoparticles.