The use of communication technologies may overcome some of the difficulties of conventional, paper-based, self-management of chronic diseases. This paper aims to describe and evaluate the use of P'ASMA – a web based asthma self-management support tool regarding the opinion of patients and their adherence to monitoring in comparison to standard paper-based tools. System description: P'ASMA allows the collection of asthma monitoring data and provides, to both patient and doctor, immediate feedback about patient's condition. For each patient a set of forms and scheduling options can be chosen. Evaluation methods: Twenty-one adults with previous medical diagnosis of asthma were included in an exploratory randomized crossover study. Patients used P'ASMA or a paper asthma diary and action-plan each during 4 weeks in a random sequence. Results: The number of patients who wrote negative remarks regarding P'ASMA was 2 and regarding paper-tools was 11; positive comments were 6 and 1 respectively for P'ASMA and Paper-based. Twelve patients were very interested to continue to monitor their asthma using P'ASMA whereas only 2 with Paper-based (p=0.002). Of the 19 problems reported with P'ASMA, 9 were related to the Internet connection, 5 to the user interface, 3 to internal system errors and 2 to the questions interpretation. The completeness of paper diary records was better; however, 10 patients reported filling it several days at once which was not allowed in P'ASMA. Conclusions: The intervention was feasible, safe and the problems detected in the web-application can be corrected. With P'ASMA data quality improved as the integrity features increase the reliability of the data. Moreover, patients preferred the web-based application to monitor their asthma.