Currently natriuretic peptides are justifiably regarded as the most promising circulating markers of cardiovascular disease in dogs and cats, but there are many other markers that can be used in the evaluation of such patients. There are markers of myocyte injury typified by troponins I and T; markers of myocyte stress including adrenomedullin and ST2; markers of remodeling including matrix metalloproteinases, tissue inhibitors of metalloproteinases and collagen molecules (PIIINP); markers of endothelial function including dimethylarginines and nitric oxide metabolites; markers of inflammation including C-reactive protein, several interleukins and tumor necrosis factor alpha; and finally neurohormonal markers. The potential of many of these markers has at best been only partially explored in veterinary patients. Evidence emerging from studies of human and in some cases veterinary patients suggests that using multiple markers may be superior to using single markers alone. As well as evaluating markers for their diagnostic value they should be considered as methods of identification of patients at increased risk of experiencing complications or death. Future areas of research in this field could include improved characterization of the clinical utility of multi-marker evaluation in veterinary patients and using markers to identify patients that may benefit from particular interventions.