The general objective of this study is, on one hand, to identify and analyse the factors that contribute to child poverty and, other hand, to identify the existence of child welfare inequality and then analyse their sources in four WAEMU countries like: Cote d’Ivoire, Guinea Bissau, Niger and Togo. Basing our methodology on multidimensional poverty approach, the results show that some factors explain the child poverty in these countries: the access to the vitamin A, the quality of iodized salt, the nursing, some vaccinations against poliomyelitis, diphtheria, the measles and the yellow fever on the one hand, and the illnesses like the diarrhoea, the cough, the fever and the respiratory difficulties on the other hand. After that an absolute child poverty line is defined, child poverty headcount has been calculated. The results indicate that child poverty headcount is 19.4% in Togo, 21.1 % in Cote d’Ivoire, 29.0% in Guinea-Bissau and 49.7% in Niger.