Pantothenic acid nutritional status was evaluated in 37 men (32 noninstitutionalized and five institutionalized) and 54 women (33 noninstitutionalized and 21 institutionalized) 65 yr of age or older. A fasting blood sample, a 24-h urine specimen and a food consumption record for 1 wk were obtained from each subject. Hematological, anthropometric, and dietary parameters indicated these 91 subjects were similar to elderly populations evaluated in other studies. Pantothenic acid was analyzed by both radioimmunoassay and microbiological assay. By combining methods it was possible to differentiate various forms and derivatives of pantothenic acid. Free pantothenic acid, but not the phosphoderivatives, was observed in urine. Microbiological and radioimmunoassay estimations of pantothenic acid showed good correlation (r = 0.91). Pantothenic acid excretion in the institutionalized subjects (7.5 +/- 1.3 (x +/- SEM) mg/g creatinine) was comparable to the excretion levels in the noninstitutionalized subjects (5.9 +/- 0.6 mg/g creatinine). Those consuming pantothenic acid supplements had significantly higher excretion levels. Blood pantothenic acid values between the groups, noninstitutionalized (537 +/- 27.4 ng/ml) and institutionalized (615 +/- 47.3 ng/ml), were comparable. The average dietary intake of pantothenic acid for the elderly population studied was 5.9 +/- 0.1 mg/day with the institutionalized and noninstitutionalized subjects having a similar intake of 2.9 mg/1000 kcal. Institutionalized elderly males and females were consuming 2237 and 1962 kcal, respectively, while their noninstitutionalized counterparts were consuming 2201 and 1887 kcal.