OBJECTIVE: The introduction of DRGs in 2004 requires German hospitals to gain cost transparency and optimize budget allocation. We compared two different chemo regimens (4 x EC followed by 4 x docetaxel q21, EC->DOC vs. 6 x CMF, day 1+8, q28) for patients with node positive primary breast cancer regarding costs of resource consumption. METHODS: Data were obtained piggyback during 2/2000-5/2002 on the German prospective, longitudinal, randomized, multicenter Phase III EC->DOC trial closed in 8/2005. Evaluation of diagnostic effort was based on a comprehensive monocentric retrospective chart review. To allocate costs to health care resources German tariffs in €2005 and hospital databases were used. Costs were presented from hospital provider perspective. Sensitivity and scenario analyses were conducted. RESULTS: Altogether a cohort of 110 patients who received 1047 cycle days at 38 study centers was analyzed. The average patient age was 52.4 years. Mean direct costs for EC->DOC group totaled €8.459 per patient (N = 54). Costs for cytostatics accounted for the largest portion with €5.673 (67%), staff costs for drug application and pharmacy services including transport averaged out €1.357 (16%), average hospital basic costs were €414 (4.9%) and €376 (4.4%) for diagnostic effort and port or catheter implantation. Hospitals spent €354 (4.2%) on supportive drugs, administration devices and infusion bags and €313 (3.7%) on rehospitalisation (8 times in 7 patients). In contrast to rather expensive EC->DOC, CMF was €3.486 less costly (-41.2%), but savings for CMF acquisition cost with -€5.598 were partially compensated by higher costs for medical and diagnostic effort or hospital hotel services. Results were most sensitive to docetaxel acquisition cost and the percentage of patients with incomplete chemotherapy. CONCLUSION: Our results will enable German hospitals to develop strategies of financing a consequential 70% budget increase caused by introducing sequential docetaxel in adjuvant chemotherapy of breast cancer.