Patients with multiple myeloma and other forms of cancer receiving pamidronate via intravenous (IV) infusion at the Hamilton Regional Cancer Centre in Hamilton, Ontario, Canada face 2 treatment options: they can have their entire treatment completed at the clinic using traditional IV therapy (e.g. IV bag and pole) or they can have the treatment initiated at the clinic and then return home to complete the treatment utilising a portable and disposable IV therapy device. To perform a cost analysis of these 2 treatment options. Societal. Data on all patients with multiple myeloma who attended the Hamilton Regional Cancer Centre for pamidronate therapy from November 1, 1997 to October 31, 1998 were collected from clinic records. As almost all of these patients with multiple myeloma completed their IV therapy at home, comparison to clinic-based therapy was based on derived cost estimates. Cost data, where possible, were acquired from the Hamilton Regional Cancer Centre's records. A sensitivity analysis was also conducted. In the base-case scenario for the study period, the incremental cost of the infusion device and training in Canadian dollars ($Can; 1998 values) for the 48 patients (299 cycles) who had their infusion initiated at the clinic but completed at home was $Can 5.50/cycle ($Can 4,636 for the 299 cycles). If these 48 patients had had their entire infusion at the clinic, the incremental costs of overtime treatment, parking, clinic overheads and lost work or leisure time would have been $Can 68.49/cycle ($Can 20,477 for the 299 cycles). Therefore, shifting treatment from the clinic to the home resulted in net cost savings to society of $Can 52.98/cycle ($Can 15,841 for the 299 cycles). Sensitivity analysis of best- and worst-cost scenarios did not alter the substantive findings although the relative difference between treatment options varied. In the best-case scenario, home treatment was $Can 95.97/cycle ($Can 28,696 for the 299 cycles) less costly than clinic treatment, while in the worst-case scenario, home treatment was $Can 17.19/cycle ($Can 5,141 for the 299 cycles) less costly than clinic treatment. The results also demonstrated that clinic overheads, the cost of a portable and disposable infusion device and the cost of lost work and leisure time had the greatest impact on incremental costs for each treatment option. Subject to study limitations, a significant cost advantage was demonstrated through the home-based treatment option for patients with multiple myeloma. Key issues that must be addressed in future evaluations include the precise determination of clinic overheads, the valuation of lost work and/or leisure time and the direct cost of portable and disposable infusion devices.