Primary spontaneous pneumothorax (PSP) is a common entity. Treatment varies widely across different health systems and even among doctors in the same department. In our general surgery department 30 to 40 patients with PSP are treated each year and there is significant variability in care delivery. This prompted the development of a clinical pathway (CP) based on analysis of the process, a search for studies with the greatest scientific evidence and professional consensus. The aim of this study was to present the results after 1 year's evaluation of the CP. A series of 34 patients treated in the year prior to the design of the pathway was analyzed to identify weak points and areas for improvement. To address these weak points the CP included associated protocols and principal documents. Thirty-one patients included in the CP were treated over 1 year and the results were compared with those of the pre-pathway series. The mean length of stay in the pre-pathway patients was 7.3 days compared with 5.0 days in the pathway patients. The number of radiographs also fell from 4.3 to 3.2. The rate of complications and re-admissions was similar in both groups. The mean cost per process decreased from 1863 Euro to 1168 Euro. The CP for pneumothorax reduced both variability in professional care patterns and hospital costs, justifying the work involved in its development and implementation.