PURPOSE: Adequate dietary protein intake is required to postpone and treat sarcopenia in elderly people. Insight into dietary protein intake in this heterogeneous population segment is needed to locate dietary inadequacies and to identify target populations and feeding strategies for dietary interventions. Therefore, we assessed dietary protein intake, distribution of protein intake throughout the day, and the use of protein-containing food sources in community-dwelling, frail, and institutionalized elderly people in the Netherlands. METHODS: Secondary analyses were carried out using dietary data collected from studies among community-dwelling, frail, and institutionalized elderly people to evaluate protein intake characteristics. RESULTS: Dietary protein intake averaged 1.1 +/- 0.3 g/kg-bw/day in community-dwelling, 1.0 +/- 0.3 g/kg-bw/day in frail, and 0.8 +/- 0.3 g/kg-bw/day in institutionalized elderly men. Similar protein intakes were found in women. Ten percent of the community-dwelling and frail elderly and 35% of the institutionalized elderly people showed a protein intake below the estimated average requirement (0.7 g/kg-bw/day). Protein intake was particularly low at breakfast in community-dwelling (10 +/- 10 g), frail (8 +/- 5 g), and institutionalized elderly people (12 +/- 6 g) with bread and dairy products as predominant protein sources. CONCLUSIONS: Whereas daily protein intake is generally well above the recommended dietary allowance in community-dwelling and frail elderly people, a significant proportion of institutionalized elderly showed an intake below the current protein requirement, making them an important target population for dietary interventions. Particularly at breakfast, there is scope for improving protein intake.