A study was conducted to examine selected nutritional and biochemical relationships in 65 non-institutionalized rural elderly female residents of Story City, Iowa. The female volunteers were mentally and physically able to participate in the study. They had no overt disease conditions and/or they were not taking any medications that would interfere with the study. Data collected by personal interview included medical history, drug usage, dietary information, height and weight history of 25 reference women (50-64 years), 28 "young-old" women (65-84 years) and 12 "old-old" women (85-92 years). Heights and weights were also measured. Fasting blood samples were obtained and analyzed for total serum cholesterol, high density lipoprotein cholesterol (LDL-C), serum triglyceride, serum immunoglobulins (IgG, IgA, IgM), serum albumin and total serum protein. Low density lipoprotein cholesterol (LDL-C) concentrations were calculated. Serum lipids were not significantly affected by age, drug use or age by drug use interaction. Mean concentrations of total serum cholesterol, LDL-C, HDL-C and serum triglyceride were 7.03 mmol/L (272 mg/dL), 5.07 mmol/L (196 mg/dL), 1.29 mmol/L (50 mg/dL) and 1.51 mmol/L (134 mg/dL). Serum lipids were not significantly related to dietary lipids. Based on one 24-hour dietary recall, the average percent of energy from fat was 29, P:S ratio was 0.51 and dietary cholesterol intake was 193 mg. Mean serum IgA concentration was influenced by age but not by drug use or age by drug use interaction. Mean serum albumin levels were significantly affected by age but not by drug use. Mean total serum protein levels were affected by drug use but not by age. For all participants, mean concentrations of serum immunoglobulins, serum albumin and total serum proteins were within normal limits. Results of this study suggest that unidentified factors other than age, drug use or age by drug use interaction greatly affected serum lipid profiles and immunoglobulins in the well-elderly women.