Children under five years are vulnerable to health and nutrition problems. The first two years period of life is a critical phase because of the growth and development of the children during this period. The purpose of this study is to analyze the situation of malnutrition in toddlers in nutritionally vulnerable districts. This study is a descriptive study using a cross-sectional approach. There are 10 respondents from Puton Village, Diwek District, and Jombang Regency as the samples of the study. The data was collected from August until September 6, 2019. The samples were collected by using a total sampling method. The dependent variables in this study are nutritional knowledge, infectious disease, and eating habits. Meanwhile, the independent variables are undernutrition and malnutrition. The data were analyzed using Chi-Square. The results of the study showed that the most influential factors in the occurrence of undernutrition and malnutrition were almost entirely (76%) influenced by eating habits, very few (15%) influenced by nutritional knowledge, and very little (9%) influenced by infectious diseases. Problem-solving in nutrition programs must be developed innovatively at the regency level with indirect intervention at the regency level, through strengthening the health and nutrition system by involving the community, local government, and related sectors.