Smallholder farmers contributes significantly to world’s food and, yet they are the most food insecure. In Indonesia, 20 million people are malnourished, while food production in rural areas largely depends on smallholder farming systems. Trees can contribute significantly to the food security. It is of interest how trees contribute to the food security of smallholder farmers. This study aims to assess household food security of smallholder farmers and nutritional status of the women and children living in Buol, Central Sulawesi. A cross sectional survey was carried in December 2015 to January 2016 in three sub-districts, Buol, Central Sulawesi. Data on general characteristics, agriculture situation, and socio-demographic were collected using a structured questionnaire. Dietary intake data of women and children were assessed using a-24-hour food intake recall. Anthropometry (weight and height) of the women and children, as well as haemoglobin level of selected women were also measured.In total 200 pairs of women and their oldest under-five children. Based on type of farming system and occupation, respondents were categorized into four groups, as follows annual- (n=69), tree-based- (n=34), mix-crop- (n=55) and non-farmers (n=42). More than 60% of tree-based farmers said that they had a side job during the last one year, perhaps due to the less- time allocated for the typical tree-based crop farming activities in the study area as compared to annual cropping activities, in addition to the need in purchasing family food. Less than 50% of the respondents utilized their gardens. The main production of annual crops was rice and nilam, while, coffee, cacao and coconut were mainly planted in tree-based field. Yearly income generated by the groups was not significantly different, however, the highest proportion of families who spent above 80% for food was found among tree-based crop farmers, followed by non-farmer because they did not cultivate food crops. The women and children in all groups suffered chronic undernutrition indicated by high prevalence of overweight/obese women, stunting and underweight among children. Similarly, anemia prevalence in all sub-sample women was also high. Prevalence of wasted children in the tree-based crop farmer families was the highest (26.5%), followed by non-farmer. Tree-based crop farmers suffer more severely due to food insecurity as compared to the other groups. Recommended actions for tackling the food insecurity are promoting mixed systems among the tree-based crop farmers, better use of homegarden for planting crops or trees as source of food, as well as nutrition rehabilitation for the undernourished women and children.