1. A genome scan was performed to locate genomic regions associated with traitsthat are known to vary in birds (most commonly broilers) suffering from heart,lung or muscular dysfunction and for weight of the dressed carcass and someinternal organs. 2. The F2 population studied was derived from a cross between abroiler and a layer line and consisted of over 460 birds that were genotyped for101 markers. 3. There was strong support for segregation of quantitative traitloci (QTL) for carcass and organ weights and blood variables. We identified 11genome-wide significant QTL (most of them for dressed carcass weight) andseveral genome-wide suggestive QTL. 4. The results point to some genome regionsthat may be associated with health-related traits and merit further study, withthe final aim of identifying linked genetic markers that could be used incommercial breeding programmes to decrease the incidence of muscular andmetabolic disorders in broiler populations.