Odour emission from poultry houses was determined for seven different systems of rearing and type of production. Odour emission was determined based on the assessment of interior odour concentration and the measurement of ventilation rate within a specified period of time. In order to assess the odour concentration, samples of ventilated air have been collected. Odour concentration was assessed in the laboratory using dynamic olfactometry, in accordance to European standard EN 13725:2003. A TO8 olfactometer was used. In order to determine the efficiency of the ventilation system, air flow was measured for each fan. Later, air exchange volume from each house was defined. Odour emission was calculated from odour concentration and air flow and expressed in odour units (ouE) per 1 kg of live hen. Average, minimum and maximum rates of emission were determined. It was found that the lowest average odour emission occurred for layers in poultry houses equipped with laying battery (0.043 ouE kg-1 s-1) and the highest for broilers raised on litter bedding (0.586 ouE kg-1 s-1). For the others hen keeping systems in Poland, the average odour emission factor were between these values.