Undernutrition among children under 5 years is still a major public health concern in low-middle-income countries such as Nigeria. Micronutrient fortification of food-based vehicles such as dairy products fortified with essential micronutrients of public health relevance can be a cost-effective, strategic approach to tackling undernutrition. The overall aim of this research is to determine the effects of multi-nutrient fortified dairy-based formulae on growth, anaemia, micronutrient status, cognitive development and gut microbiota in Nigerian late preterm (LP) infants and moderately malnourished toddlers. The outcome of our research showed that multi-fortified dairy-based formula improves anaemia, selenium, Vitamins A and D status in and moderately malnourished Nigerian toddlers. Also, unfortified breastmilk is sufficient to support adequate growth in LP infants.