The objective of the study was actually the investigation of the effect of various organic wastes on the ability of urine in absorbing CO2. Urine alone or mixed with olive-oil-mill waste waters (O), poultry litter (P) or meat bone meal (M) was used on the absorption of CO2 from a gas bottle. The absorption capacity (1.35 - 2.85 gCO2/gNH4) was bigger than other solvents such as ammonia and amines. The range of CO2 absorption was significantly bigger for the organic mixtures P and PM with urine (9.1 - 11.8) g/L than urine alone 6.5 g/L. These organic wastes could be used to increase CO2 absorption in urine and reduce gas emissions.