To assess the association between sociodemographic factors and factors related to number and type of comorbidities, and presence of severe disability in a population of adults applying for disability certification. Data have been collected using a protocol based on the ICF Classification. Hierarchical logistic regression was performed to assess the association between severe disability and sex, age, marital status, education, living situation, number, and type of diagnosis. In total, 552 individuals were enrolled (46.2% men, mean age 62.3 years), with an average of three diagnoses, mostly mental, neurological, and cardiovascular. Being married/cohabitating and higher education levels were associated with reduced odds of severe disability; living with other individuals, such as in an institution, was associated with increased odds. Our results show that age and education level were associated with severe disability, and that no association with number of diseases was found: in our opinion, this is specific to the population of individuals with disability.