The sustainability of dietary plant and animal protein consumption is an important issue, but few data are available to ascertain the health-related impact of animal and plant protein intake. The objective was to study the relationships between animal and plant protein intake and diet quality, as reflected by an integrated index of nutrient adequacy. Using data on 1912 adults from the French Individual and National Consumption Survey 2 (2006-2007), we assessed diet quality by using the PANDiet, a unique score combining 35 probabilities of having an adequate nutrient intake, and used multiple regression analysis to study the relationship with intakes of plant, animal, and related food source proteins. After adjustments for intakes of energy, alcohol, and protein from other sources and sociodemographic factors, plant protein intake was positively associated with the PANDiet, irrespective of sex (β = 0.50, P < 0.0001). By contrast, total and animal protein intakes were differently associated with the PANDiet according to sex, with a positive association in women (β = 0.07 and β = 0.08, respectively; P < 0.01) and an inverse association in men (β = -0.07 and β = -0.05, respectively; P < 0.01). The relationships between the PANDiet and intakes of protein from animal food sources varied: for instance, associations were inverse for red meat and poultry in men but not in women, whereas irrespective of sex, they were positive for fish, milk, and yogurt and inverse for processed meat, cheese, and eggs. These findings show that plant protein is a robust marker of a healthy diet, whereas total animal protein includes different subtypes of animal protein that largely vary in their relationship with diet quality. These data could help refine protein recommendations from a qualitative and dietary standpoint.