A few observational studies and randomized trials suggest that exercise and rehabilitation may improve activity limitation and quality of life (QoL) in patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), but the impact of other modifiable factors on the severity of the disease is not well understood. Using a structured questionnaire, we collected data on lifestyle and dietary habits of the patients included in the Italian CIDP database to investigate the possible influence of modifiable lifestyle factors on disability and QoL. Questionnaire data were available for 323 patients. The effect of lifestyle and dietary exposures on impairment, disability and QoL was evaluated using logistic regression models, adjusting for age, sex, disease duration, physical activity and smoking. Physical activity was associated with lower sensory impairment by the ISS scale, less disability by the INCAT and RODS scale and a better QoL in all the domains of EURO-QoL scale with the exception of anxiety/depression. None of the other parameters had an impact on these scales. This study adds evidence to the possible role of physical activity in improving symptom severity, disability and QoL in patients with CIDP. None of the other environmental factors investigated appeared to have an impact on the severity and health perception of CIDP.