By using information derived from questionnaires sent to registered owners of drever dams and sires in Sweden with offspring born in 1992 and/or 1994, two groups of offspring were identified: one with one parent said to have had breathing difficulties after hunting, and another with both parents unaffected. Questionnaires were sent to the owners of these offspring, and multiple logistic regression was used to analyse the offspring data, with the status of their sire and dam with respect to breathing difficulties after hunting included as covariates. For the outcome 'breathing difficulties after hunting' in the 266 offspring, the odds ratio (OR) was 4.4 (95 per cent confidence interval [CI] 1.8 to 10.8) if the dam was affected and 3-9 (95 per cent CI 1.2 to 11.1) if the sire was affected. The OR for male offspring was 2.4 (95 per cent CI 1.1 to 5.7). The heritability of the condition was estimated to be 0.34 from the dogs born in 1992, and 0.28 from the dogs born in 1994.