The purpose of the present study was to evaluate the influence of nutrition, age, and Vitamin D status on fasting urinary calcium (Ca) as a function of creatinine excretion (Ca/Cr) and of glomerular filtration rate (Ca/GFR) in postmenopausal women. Fasting urinary calcium, urinary Cr and GFR were measured in 18 women aged 54 to 91 years before and after six days of a calcium (400 mg/die) and sodium (100 mEq/die) restricted diet with a controlled content of proteins, lipids and glucides. Aged (over 64 y.) women having an adequate vitamin D status showed fasting urinary Ca/Cr and Ca/GFR after the controlled diet significantly lower than those showed before. It is concluded that fasting Ca/Cr and Ca/GFR may be nutrition-dependent. A revision of the significance of the fasting urinary Ca excretion is consequently suggested.