Suck dysfunction in breastfeeding infants has an impact on their appropriate nutrition. The objective was to build and validate one clinical nutritional sucking scale in the components of sucking, swallowing, and respiration. The scale was carried out in two phases: face-validity and psychometric validity. The first was done by expert consensus. For the second phase, 179 infants (153 healthy newborn and 26 infant less than 6 month of age) and 86 infants with high risk for abnormal sucking were evaluated with the new scale. Three observers evaluated all patients during their feeding. With an initial scale of 10 items we calculated the inter-observer concordance and the internal consistence. With an analysis of the mail components and a discrimination index we reduced to pertinent items. Each component of the scale was compared with clinical variables. We reached a 7 items scale, which showed high reliability (Cronbach's alpha of 0.77 and inter-observer concordance of 0.98. The suck component correlated positively with the ingested volume (Ro = 0.61), the swallow component with the peripheral oxygen saturation (Ro = 0.24), and the breath component with the respiratory frequency (Ro = 0.50). With this scale, we can establish different patterns of sucking abnormalities related with history of neurological abnormalities, hemodynamic alteration and immaturity. In this study the clinical nutritional scale showed to be reliable and valid for its use in sucking problems classification. More studies are required to evaluate its application for oral stimulation therapies.