Anaerobic co-digestion is effective and environmentally attractive technology for energy recovery from organic waste. Organic, agricultural and industrial wastes are good substrates for anaerobic co-digestion because they contain high levels of easily biodegradable materials. In this paper enhancement of biogas production from codigestion of whey and cow manure was investigated in a series of batch experiments. The influence of whey ratio on specific biogas production in a mixture with cow manure was analyzed at 35 and $55^{circ}C$, for different initial pH values and for different concentrations of supplemental bicarbonate in experiments carried out over 12 days. Good biogas production (6.6 $dm^3/dm^3$), methane content (79.4%) in a biogas mixture and removal efficiencies for total solids (16%) were achieved at optimum process conditions (temperature of $55^{circ}C$, 10% v/v of whey and 5 g/$dm^3$ $NaHCO_3$ in the initial mixture). In order to validate optimized conditions for co-digestion of whey and cow manure in the one-stage batch process, the experiments were performed within 45 days. The high biogas production (21.8 $dm^3/dm^3$), a good methane content (78.7%) in a biogas mixture as well as maximum removal efficiencies for total solids (32.3%), and chemical oxygen demand (56.3%), respectively indicate that whey could be efficiently degraded to biogas in a onestage batch process when co-digested with cow manure.