The Medical Society of Western Greece and Peloponnesus (IEDEP) resulted from the enlargement of the Patras Medical Association, which is the most long-lived Medical Society in Greece, after the Medical Society of Athens.

The Medical Society of Patras was founded in Patras in 1912, aiming to provide further training for doctors, engage its members in the discussion and scientific study of public health issues, and build closer relations among its members.

In 1969, it expanded to include physicians from neighbouring Medical Societies (Aegio, Amaliada, Pyrgos, Agrinio, Zakynthos and Cephalonia) changing its name to Medical Society of Western Greece (IEDE). In 2003, it expanded further to include all medical associations in the Peloponnese, and was thus renamed as the Medical Society of Western Greece and Peloponnesus (IEDEP).

From the very start, it set its objectives and activities apart from those of the Medical Association (the medical union).

The IEDEP focuses mainly on the organisation of scientific events (Roundtables, Meetings, Lectures, Conferences, etc.) in Patras and periodically in other cities in its jurisdiction.

Since 1975, the IEDEP publishes the peer reviewed journal ACHAIKI IATRIKI, in collaboration with doctors from the Peloponnese, other areas of Greece and abroad.

The IEDEP contributed significantly to the creation and establishment of the Medical School of the University of Patras (1975), with which it cooperates closely.

In 1986, it established the Medical Awards for Pathology, Surgery, and the History of Medicine, while it recently established a Primary Health Care Award.

In the same year, it undertook the initiative of establishing a Museum of Medicine in the premises of the Old Hospital of Patras; the project is still under construction.

In 1994, the IEDEP introduced the institution of the Pan-Peloponnese Medical Congress, co-organized with medical associations throughout the Peloponnese, and held every two years with great success.

It has also introduced two other conferences, the Achaikes Imeres Pathologias (Achaia Medical Days) and the Achaikes Imeres Chirourkikis (Achaia Surgical days), every second year alternately.

In addition, throughout the year, in collaboration with various specialties, departments and institutions, it organizes many other scientific and social events and tours in Greece and abroad, to allow its members to meet, communicate, and build close relations. It confers awards to colleagues in its jurisdiction who have distinguished themselves through their contribution to medical science.

The IEDEP is based in Patras and is managed by a 13-member Board with a three-year term, elected from a single ballot.