Background <p>Malnutrition remains a significant public health challenge in low-middle-income countries, particularly in rural and ethnic communities where structural inequalities exacerbate health disparities. This study aimed to examine the socioeconomic, cultural, and healthcare factors influencing malnutrition in children under two years old in three vulnerable regions of Colombia: Guajira, Cesar, and Chocó.</p> Methods <p>A mixed-methods approach was utilized, combining quantitative analysis with qualitative interviews exploring cultural practices and healthcare access. Data was collected from clinical records of 269 children under two years diagnosed with severe and moderate acute malnutrition, data were stratified by region, ethnicity, and maternal education levels. The socioeconomical analysis includes a geographical analysis according to the location of the households.</p> Results <p>Socioeconomical disparities, with over 52% of households living on less than $125 USD per month, limited access to complementary foods, and high food insecurity characterized by families eating only once or twice a day. Prolonged exclusive breastfeeding over six months was observed in 10.7% of cases, influenced by cultural beliefs and food insecurity. Health complications, such as diarrhea and respiratory infections, were the most prevalent, where systemic barriers to healthcare access were most evident.</p> Discussion <p>These findings align with global evidence from the WHO Global Nutrition-Report, which highlights the critical role of poverty, food insecurity, and inequitable healthcare access in perpetuating malnutrition. The study underscores the urgent need for culturally sensitive interventions, social protection programs, and infrastructural investments to address these disparities. By integrating local cultural contexts with evidence-based strategies, targeted-policies can improve maternal and child nutrition outcomes in Colombia’s most vulnerable regions.</p>