OBJECTIVES: This work aimed to develop rigorous models of the Australian costs of four common chemotherapy adverse event (diarrhoea, vomiting, anaemia and neutropenia), which provide standard cost estimates and can be used in future models of chemotherapy cost effectiveness. METHODS: Decision analytic modelling was used to identify the costs and consequences of AEs.  These are not only stand alone models, but also form decision tree sections to be incorporated into larger models of chemotherapy cost effectiveness. Model structures are based on best-practice clinical pathways, and incorporate efficacy of side effect treatment, quality of life and chemotherapy dose.  Literature reviews identified clinical inputs. Costs of treatment were obtained from standard Australian sources such as the Pharmaceutical Benefits Schedule. The perspective was the Australian health care system.  One-way sensitivity analyses explored uncertainty in the models.  RESULTS: The base case average cost per patient of diarrhoea ranged from $19 (mild AE) to $4,821 (severe AE); those for anaemia ranged from $51 (mild AE) to $17,100 (moderate AE) depending on the type of chemotherapy and anaemia treatment.  Vomiting prevention base case costs ranged from $0.84 (low risk chemotherapy) to $157.55 (high risk chemotherapy requiring breakthrough and refractory management). Neutropenia base case costs ranged from $2,235 (outpatient management) to $12,054 (intensive care required). Where possible, the impact on quality of life and chemotherapy total dose was also modelled. Estimates of AE costs vary widely in the literature, however our estimates appear consistent with studies of similar methodology. CONCLUSIONS: The four models presented represent best-practice modelling techniques for chemotherapy AEs.  Each has been designed to enable either the results or the model structure to be incorporated into larger models of chemotherapy cost effectiveness. This allows model builders to incorporate rigorous, Australian-specific estimates of the costs and consequences of chemotherapy AEs into models of chemotherapy cost effectiveness.