Breastfeeding is the gold standard nutrition for infants. However, the inability of infants to latch on, maternal complaints of sore or painful nipples, and insufficient milk supply frequently result in early breastfeeding cessation. Hence, milk has subsequently been replaced by infant formula milks of high quality, which serve as an alternate source of nutrition for infants. There also has been a rising concern among parents and caretakers regarding the cariogenic potential of the various milk formulas available in the market due to the presence of fermentable carbohydrates in them, leading to an increase in nursing caries or early childhood caries. Hence, this study aims to comparatively evaluate the acidogenic potential of four different milk formulas based on dental plaque pH, salivary pH, and buffering capacity. This cross-sectional study was carried out to assess the acidogenic potential of various infant milk formulas using three main parameters of measurement of caries: evaluation of salivary pH, plaque pH, and buffering capacity.Baseline plaque and salivary pH and postconsumption plaque pH and salivary pH were assessed after 5, 10, 15, 20, 30, and 60 minutes in 60 healthy children (15 in each study group) aged 7-12 years after rinsing with group I (lactose-based), group II (soy-based), group III (protein hydrolysate-based), and group IV (iron-based) milk formulas. The pH was assessed using a precalibrated digital pH meter. Plaque pH was also further assessed based on its buffering capacity. Soy-based and protein hydrolysate-based milk formulas were found to be most cariogenic in both saliva and plaque. Lactose-based formulas were found to be the least cariogenic of all the milk formulas. Parents and caretakers must be made aware of the various types of milk formulas available, their composition, as well as their relative cariogenic nature. Feeding should always be supervised, and infants should not be left with milk-containing bottles as comforters. Milk feeds at bedtime, when salivary flow is reduced, should be discouraged. Dentists and pediatricians should be aware of the caries-related risk associated with different milk formulas before recommending them to children. Knowledge and awareness among parents and caretakers regarding the cariogenicity of various milk formulas available in the market. Mahanta A, Yadav G, Saha S, et al. A Comparative Evaluation of the Acidogenic Potential of Lactose-based, Soy-based, Protein Hydrolysate-based, and Iron-based Milk Formulas Based on Dental Plaque pH, Salivary pH, and Buffering Capacity: An In Vivo Study. Int J Clin Pediatr Dent 2024;17(8):851-859.