The aim of this study was to evaluate the problems found in performing chest physiotherapy (PKT) by patients with Cystic Fibrosis (CF) and by their families. The research has been based upon processing 389 questionnaires (46 items) that were compiled by the families. Thirteen CF centers all over the nation have participated in this study. Patients' mean age was 7.4 years (range 2 months to 14 years). Data about the socio-economic status and illness severity were available for every patient. Many graphs (line connects points with a line = n. 8; bar charts = n. 17; pie charts = n. 13) show the results and their statistical processing. Our purpose was to solve the following problems: 1) What is the extent of the compliance? 2) Who perform, or should perform, PKT in the family environment? 3) What is the kind and extent of the help request? 4) What are the mistakes made in executing PKT? 5) What is the usefulness of precursors and aerosol therapy? 6) What is the link between physical activity and PKT? 7) What are the main difficulties in performing PKT? 8) How effective is PKT? 9) What is the extent of the parents' faith in their capabilities? 10) Are there any prejudices against PKT? Three major findings emerge from this study: 1) the compliance appeared good; 2) the average family understood the meaning of PKT correctly and 3) PKT is usually executed properly. As for negative results are concerned, it is to be noted that the burden of performing PKT is usually up to the mother. This finding is linked both to the socio-economics status of the family and to the severity of the illness. On the other hand, a home PKT service is only asked in very extreme situations such as sudden worsening of the patient's illness. The difficulties met in performing PKT range from the patient's refusal to logistical and organization problems, which are correlated with the socio-economic status of the family. The relationship between PKT and sport is understood well and there is a high percentage of patients doing regular physical activity, even if it is often hindered by the severity of the disease. In conclusion, although there are many problems, there are also many methods to use in order to improve the acceptance and the effectiveness of the PKT.