Objective: To determine the incremental cost-effectiveness ratio (ICER) of cinacalcet as an adjuvant therapy for SHPT from the perspective of the Portuguese NHS. Methods: A probabilistic Markov model was used to compare best standard care (BSC) with BSC plus cinacalcet. The model was developed in cycles of six months until the death of all patients. Patients were distributed according to the risk of hospital admission due to cardiovascular events, major or minor fractures and parathyroidectomies. The absence of events and/or death was also considered. The probabilities of SHPT's complications were obtained from the literature. Portuguese official mortality rates were weighted by the presence of renal insufficiency and by the PTH levels. Due to lack of alternative, the resources used (only direct medical costs) were estimated by a Delphi panel of eight nephrologists and by a physical medicine and rehabilitation specialist. Unit costs were obtained from Portuguese official sources. Market shares of medicines prescribed in outpatient services were selected from the IMS. Results: Cinacalcet increases 0.4 life years (LY) per patient with SHPT. The use of cinacalcet saves hospital admissions and follow-up costs of secondary events, but is associated with an ICER of €53,682 per LY gained. However, if dialysis costs are not considered, the ICER is €32,374 per LY gained and the probability of being cost-effective increases from 61% to 83% if acceptability for reimbursement is limited at €50.000 per LY gained. Conclusion: Using a €50,000 WTP threshold, cinacalcet was found cost-effective if the increased cost of dialysis was excluded. The inclusion of this cost (induced by a longer life expectancy) leads to an ICER of €53,682 per LY gained. A clear paradox arises here as the alternative becomes less cost-effective by increasing dialysis patients' longevity.