Raising beef cattle in open feedlots is a well established practice in Canada and is gaining acceptance in Australia because it results in more consistent meat quality. These facilities are regional ‘hot spots’ of methane (CH₄) emissions, resulting from the high stocking density and the large amount of fermentation occurring in the rumen (enteric CH₄). Our objective was to compare CH₄ emissions from a typical feedlot in Australia (Queensland) and in Canada (Alberta) and also to compare these against modelled emissions. Methane concentration and wind data were monitored over a portion of each feedlot and a dispersion model was used to calculate CH₄ emissions during a summer period. The average CH₄ emission was 166 ± 90 and 214 ± 61 g/animal.day for the feedlot in Queensland and in Alberta, respectively. The lower CH₄ emission at the Queensland feedlot was attributed to the lighter weight of the cattle, and consequently their lower intake, and supplementation of the diet with lipids. The lipid effect on CH₄ emissions is also speculated to cause some models to overestimate the measured CH₄ emissions. A lower CH₄ emission also occurred during daylight hours at the Queensland feedlot and was attributed in part to heat stress as defined by the temperature–humidity index.