In Italy, unlike in other European countries, the public health burden of work-related asthma (WRA) has not yet be defined by means of a standardized validated epidemiological metric. The aim of the present study is to describe the methodology for the calculation of the Burden of Disease of WRA in Tuscany on the grounds of available healthcare and health survey data. The paper is particularly intended to illustrate the methodological approach to estimate the prevalence of the disease.