The aim of the study was to determine in laboratory conditions CH4 and CO2 emissions from a soil with including redox potential (Eh). Experiment was carried out under laboratory conditions on Ap horizon of a loess soil (Orthic Luvisol) flooded with water and municipal waste water after second step of purification. Soil samples were incubated in the darkness at 20oC for 15 days. During incubation, concentrations of CH4 and CO2 from the soil were analysed by gas chromatography. Parallely with gas analyses Eh and pH measurement were done. The maximal emission of CH4 reached values of 0.007 mg C-CH4 kg�1 on the 7th day in the samples treated with waste water. The incubation of soils in 20oC resulted in 30% higher CO2 emission with waste water than in the samples treated with water. Redox potential was decreasing to about �110 mV until the 6th day and keep this value to the end of experiment. The maximum emission of CH4 was observed at Eh �119 mV in the soil flooded with waste water.