Protein, carbohydrates, and fats comprise the macronutrient components of infant formulas. While all infant formulas in the United States meet specific nutrition standards, the macronutrient composition of formulas is diverse. Each macronutrient in the formula may play a role in treating or managing the disease. In addition, many formulas are marketed as resembling the composition of human milk or improving symptoms such as colic and irritability. For these and other reasons, families are often interested in different formula properties. When choosing a formula for their infant families, they may reach out to clinicians for advice. Therefore, clinicians need to understand the macronutrient composition of the formulas their patients are using. This manuscript discusses the macronutrient composition of term infant formulas and indications of the use of different macronutrient components.