BACKGROUND: The gap between health needs and available resources leads to daily rationing decisions within the health system. We have explored whether procedures exist that can promote legitimate priority decisions in connection with implementation of new and expensive technology; implementation of new treatment regimes for colorectal cancer and breast cancer in Norway in 2005 are used as examples. MATERIAL AND METHODS: This is a qualitative case study. The theoretical framework: "Accountability for reasonableness" was used to evaluate the introduction of the cancer drugs cetuximab (Erbitux) and trastuzumab (Herceptin). Data sources were official documents, newspaper articles and scientific publications with relevance to the priority setting debate concerning cetuximab and trastuzumab. RESULTS: Both cases illustrate hard choices with reasonable disagreements about values and data interpretation. The cases illustrate lack of publicity of both the decisions and their rationales. Cetuximab is less effective and costs more than trastuzumab. Weighting of cost and effect varied between the decision-makers. There are no formal mechanisms for appeals for patients who don't get the treatment they feel they are entitled to. INTERPRETATION: When these two priority cases were debated there were no established institutions or implemented procedures to facilitate an open and explicit priority setting procedure taking into consideration reasonable disagreement on substantive values.