Mothers' nutritional knowledge plays a critical role in the fight against childhood malnutrition, particularly regarding infant feeding practices. Inadequate knowledge is linked to high neonatal mortality rates. Conversely, mothers with better knowledge can contribute to improved feeding practices, potentially reducing the prevalence of this disease and its negative consequences. This study aimed to assess the level of nutritional knowledge among mothers participating in the Cabinda Integrated Project. Employing a cross-sectional quantitative design, the study enrolled 372 mothers of children under five during a four-month period (January-April 2023). A probability sampling technique with a Raosoft sample size calculator ensured representativeness. Data collection utilized two questionnaires: the Sociodemographic Variables Questionnaire and the Questionnaire for Evaluating Parents' Knowledge on Infant Complementary Feeding. Chi-square tests (p < 0.05) analyzed relationships between variables. Analysis revealed that a majority (51.34%) of mothers demonstrated adequate nutritional knowledge. Interestingly, a statistically significant disparity emerged between income, area of residence, and knowledge. Mothers from lower socioeconomic backgrounds displayed higher knowledge (60.87%) compared to those with income (p = 0.0001). Similarly, mothers in rural areas (75.80%) exhibited superior knowledge compared to urban counterparts (33.49%) (p = 0.000). Notably, no significant association was found between nutritional knowledge and educational attainment or age. The study concludes that nearly half of the mothers possess adequate nutritional knowledge. However, income and area of residence appear to have a stronger influence than education or age. This suggests that solely focusing on education and age may be insufficient to improve mothers' nutritional knowledge.