The implementation of nano-sized TiO2 dispersions for mass coloration of polyimide fibers is considered in the paper. Titanium dioxide (TiO2) is not classified as hazardous according to United Nations (UN) Globally Harmonized System of Classification and Labeling of Chemicals (GHS). The stability of TiO2 dispersions in dimethylformamide (DMF) medium in presence of different surfactants as well as the viscosity of poly(amic) acid spinning solutions was investigated. It was illustrated that nano fraction of mineral pigment increase the stability of spinning medium. Moreover, the introduction of 4,5% TiO2 in poly(amic) acid stabilized with 0,24% of surfactant (leukanol) caused the increasing of thermal stability on 10°C in comparison with non-colored fibers. Proposed method enables to get light colours and improve the thermal stability of polyimide fiber. The application of TiO2 in the mass coloration of fibers does not cause dangerous effect on consumer because the pigment is tightly connected with polymer inside fiber structure.