Environmental Factors which Influenced Child Mortality in West Sumatra Oleh Edi Ariyanto, Elfindri, Riki R No. Kontrak : 089/J.16/PL/DIPA/IV/2005 ABSTRACT Under five mortality rate has been identified as one of the key indicator used to monitor and evaluate health status and to access improvement in health development. One of the factors affecting the under five health status is exogenous factor. There is a linier association between the impact of exogenous factor and the age of children. The purposes of this research is to analyze the affect of environmental factor in decreasing the under five mortality rate in West Sumatera. With using logistic model, estimation is derived from National Socioeconomic Survey (Susenas) 2000 and 2004. The result of 2004 Susenas indicates that under five mortality rate in West Sumatera is around 46 per 1000. Statistically, under five mortality rate is influenced by source of drinking water, type of latrine, and distance between source of drinking water and septitank.