Peste des petits ruminants (PPR) is an infectious, contagious and inoculable disease. It is widely distributed in Africa, the Middle East and Asia. It was described for the first time in Côte d'Ivoire by Gargadennec and Lalanne in 1942. This pathology, similar to rinderpest at the clinical and antigenic level, reveals a capital and growing importance and constitutes a brake on the development of the breeding of small ruminants because the economic losses are considerable (morbidity is 100% and mortality 90%). The pathogen is a virus belonging to the genus Morbillivirus, the family Paramyxoviridae. This widespread and devastating disease of small ruminants causes very significant losses to the economy, food security and the livelihoods of pastoralists. Globally, it is one of the priority diseases indicated in the five-year of global action plan of the FAO-OIE Global Framework for the Progressive Control of Transboundary Diseases (GF-TADs). The Republic of Chad, like other countries has joined this line with an ambition of its eradication by 2025. The existence of PPR in Chad has been demonstrated for a long time, but no data exists for the moment on the factors of its introduction and spread in the country. This article describes the main factors behind its introduction and spread in the country.