Systemic sclerosis (SSc) presents with a great deal of variability from patient to patient and classification and subset criteria will be analysed and discussed. SSc has been reported in people from all over the world. The prevalence and incidence, however, varies from country to country and within the same country in different ethnic groups. These differences will be elucidated. Genetic and environmental factors associated with the disease will be discussed.SSc is predominantly a female disease, with the female:male ratio ranging from 3:1 to 8:1 and being higher in childbearing years. Progenitor cells acquired during pregnancy have been suggested to play a role by inducing a graft-versus-host disease (microchimerism). Recent epidemiological studies on the relationship between SSc and previous pregnancies will be discussed. SSc is associated with a significant morbidity and mortality. Survival has improved in the last 15 years. Factors associated with such improvement will be analysed.