The harmful effects of syphilis and HIV infection on the health of women and their newborn babies are well known. Knowledge of the epidemiology of these diseases in a given environment is a prerequisite and a corollary to any intervention in the field, as international data is difficult to transpose. In this book, we aim to add to the knowledge of health professionals about these two diseases, to report their seroprevalence in eastern Algeria, to provide temporal, spatial, clinical and behavioural information about women of childbearing age in the communes of Sétif and Ain El Kébira, to guide intervention and health education campaigns in order to raise awareness among populations at risk of these diseases and to contribute to improving the health of all women of childbearing age and their reproduction. We know enough today to save millions of lives; the challenge is to put this knowledge into practice!