The increasing use of nanoparticles (NPs) in recent years has posed a potential threat to the natural ecosystem. The aim of this study was to determine the C and N mineralizations of different textured (clay and sandy) soils at increasing doses of (25, 50 and 100 mg kg(-1)) TiO2 NPs and ZnO NPs that are biological synthesized from Peganum harmain L. plant extract, and to reveal their potential effects on the soil ecosystem. The carbon (C) and nitrogen (N) mineralizations were respectively determined by the CO2 respiration method and the Parnas-Wagner method under the controlled laboratory conditions for 42 days (28 degrees C, 80% of field capacity). The highest carbon mineralization among all applications was in clay soils mixed with 100 mg kg(-1) TiO2 NPs. In clay soils treated with ZnO NPs, the treatment of 50 mg kg(-1) ZnO NPs increased microorganism activity (P < 0.001). Carbon mineralization rates were found to be higher in sandy soils compared to clay soils (P < 0.05). It was observed that these rates were higher in the TiO2 NPs treated soils compared to the ZnO NPs treated soils. The nitrogen mineralization ratios were found to be higher in clay soils compared to sandy soils. All of these results indicate that the microorganisms affected from both the presence of TiO2 NPs and ZnO NPs and differences of texture in these two soils.