The results of the experimental study of the thermophysical properties of the R141b refrigerant, R141b/Span-80 surfactant solution and R141b/Span-80 surfactant/TiO2 nanoparticles nanofluid are presented. The content of both the surfactants and TiO2 nanoparticles in the objects of the study was 0.1 wt. %. The measurements have been performed along the liquid-saturation line in the temperature ranges of (273...293) K for the density, (293...343) K for the surface tension, (300...335) K for the kinematic viscosity, (293...348) K for the thermal conductivity and (261...334) K for the specific isobaric heat capacity. It was shown that the effect of surfactants and TiO2 nanoparticles on the density of the R141b refrigerant was insignificant and within the uncertainty of the experimental data (up to 0.08%). Additions of both the surfactants and TiO2 nanoparticles contributed to a decrease in the surface tension of R141b by up to 0.3% in comparison with pure R141b. Additives of both the surfactants and TiO2 nanoparticles in R141b contributed to an increase in viscosity of (0.8...1.0) %, and additives of surfactants led to a significant decrease in viscosity – by (3.5...5.0) % compared to the viscosity of pure R141b. It was shown that surfactant additives in R141b did not significantly influence the thermal conductivity (the effect did not exceed 0.25 %), and additions of both the surfactants and TiO2 nanoparticles lead to an increase in the thermal conductivity of the refrigerant by (0.3...1) %. A decrease of the specific isobaric heat capacity by (1.5...2.0) % was observed by adding the surfactants and TiO2 nanoparticles to R141b. The slight increase in the specific isobaric heat capacity by adding the surfactants to R141b was observed  (up to 1.0 %). It was concluded that the influence of the addition of nanoparticles and surfactants on the thermophysical properties of the R141b refrigerant is ambiguous and unpredictable. The results of experimental studies on the effect of nanoparticles on the thermophysical properties of a refrigerant confirm the importance of developing methods for predicting these properties. This method can be based on taking into account the presence of a structured phase of the base fluid or surfactant molecules on the surface of nanoparticles