In the present study, the effect of bioaugmentation strategy on the sequencing batch reactor (SBR) performance while treating reject water and municipal wastewater under various temperature conditions was examined. The experiment was performed in two lab-scale SBRs, each with the active volume of 8 L and operating at sludge retention time of 3 d. For bioaugmentation, a mixture of wild-living Bacteria and Archaea in a dose 0.25 mL was added to SBR A, while SBR B was a control one. Both reactors were fed with a mixture of wastewater and 13% v/v reject water. The study was divided into 5 phases, with different temperature range, each one lasted 14 d. The temperatures were investigated in 5°C increments, i.e. 20, 25, 30, 25 and 20°C.The obtained results indicated that in the bioaugmented reactor (SBR A), lower concentrations of NH4+ - N, TSS, NO2--N in effluent were found as compared to non-bioaugmented one (SBR B). In the case of NH4+ - N, regardless the temperature, the observed differences were statistically significant. Importantly, in both SBRs, the process was carried out in a stable way.