This study assessed the ranking of dairy cows using individual-level correlations for methane (CH4) emission on-farm using sniffers and in respiration chambers. In total 20 lactating dairy cows, ten Holstein and ten Jerseys were recorded using sniffers installed in milking robots for three weeks of lactation and subsequently in respiration chambers (RC) where they were each recorded on three occasions within the RC. Bivariate linear mixed models were used to determine the individual-level correlations (rI) between sniffer and RC phenotypes as proxies for genetic correlations. Despite differences in feeding and management, the predicted CH4 production from sniffers correlated highly with RC CH4 production rI = 0.77 ± 0.18 and CH4 breath concentration correlated nearly as well with RC CH4 production rI = 0.75 ± 0.20. These correlations between sniffers on-farm and RC demonstrate the potential of sniffers measurements as large-scale indicator traits for CH4 emissions in dairy cattle.