The effect of chronic ethanol ingestion on fecal and urinary excretion of calcium and magnesium was determined in male rats. The rats were given either 30% ethanol in drinking water and Purina Rat Chow ad libitum (alcohol group) or were pair-fed to the alcohol group, with starch substituted isocalorically for ethanol (pair-fed group). The animals were housed individually in metabolic cages and urine and feces collection was carried out over a period of ten days. Alcohol feeding slightly decreased and pair-feeding slightly increased body weight over the ten-day period, but the differences in body weights were not statistically significant. The fecal calcium excretion was significantly higher and the fecal magnesium excretion was significantly lower in the alcohol group than in the pair-fed controls. The urinary losses of calcium and magnesium were not significantly affected by alcohol intake. The results indicate that chronic administration of alcohol to rats in their drinking water as a sole source of fluid increases fecal calcium excretion, which could result in calcium depletion.