We evaluated whether the implementation of a nationwide clinical practice guideline for diagnosis, treatment and follow-up of laryngeal carcinomas led to changes in hospital costs, balanced against clinical changes observed following the guideline's implementation. Charts of 822 patients with larynx carcinoma (459 treated before the introduction of the guideline and 363 thereafter) in five hospitals were retrospectively investigated. In all phases, no differences in total hospital costs were observed after the guideline's implementation. Total mean costs were Euro 3,207 (95%CI 3,091-3,395) for diagnosis, Euro 3,169 (2,153-4,182), Euro 5,026 (3,996-6,057), Euro 6,458 (5,579-7,337), Euro 8,037 (7,469-8,606), Euro 12,765 (10,763-14,769), Euro 19,227 (16,848-21,605) for treatment of dysplasia, carcinoma in situ, T1, T2, T3 and T4 carcinoma, respectively, and Euro 1,856 (1,491-2,220) for 1 year disease-free follow-up. In an earlier study, we observed several positive changes after the guideline's implementation. Balanced against the equal costs before and after the guideline's implementation, we conclude that the efficiency of the care process improved.