This research was conducted in a batch mode in a laboratory-scale setup to study (1) the biodegradation of laundry wastewater under aerobic and anaerobic conditions and to quantify the degradation at steady-state in terms of kinetic parameters and (2) the inhibition caused by laundry wastewater on growth-substrate utilization by un-acclimated ethanolenriched aerobic and anaerobic microbial cultures. The chemical oxygen demand (COD) removal was above 95% under aerobic condition; however, the COD removal varied between 70 and 88% under anaerobic condition. The steady-state kinetic parameters k, Ks, Y, μm, and kd were 1.75 d-1, 21.67 mg COD/L, 0.4 mg volatile suspended solids (VSS)/mg COD, 0.7 d-1, and 0.06 d-1 respectively under aerobic condition; corresponding values under anaerobic condition were 4.7 d-1, 173.67 mg COD/ L, 0.06 mg VSS/mg COD, 0.3 d-1, and 0.04 d-1. Laundry wastewater caused a competitive inhibition at doses above 200 mg/L under aerobic and anaerobic conditions.