Poor nutritional intake in children (children under five) that is not immediately addressed can develop
into malnutrition. Malnutrition is a disease that worries the community a lot, especially in Pohuwato
district. In recent years, the government has tried to reduce the number of sufferers of malnutrition
from year to year, but the cause is not only due to family economic factors but also due to lack of
supervision of children due to the busyness of parents working as fishermen, farmers or laborers. In
addition, the limited knowledge of the community, especially parents, in detecting early symptoms of
malnutrition experienced by their children. The implementation of the Certainty Factor method can be
used to build an expert system to diagnose malnutrition. The results of this study provide initial
diagnostic results that describe the level of expert confidence with certainty values through the
application of the certainty factor method that has passed through a series of system tests using black
boxes with the results in the truth table. This shows that the overall observation of the system has
results in accordance with the input. So that, this system is able to help the community in knowing the
early symptoms of malnutrition in children.