To better understand the effect of alcohol consumption on the bone remodeling process in vivo, we used a rodent animal model system to compare osteoblast activity and number in alcohol-fed, pair-fed, and chow-fed animals. Adult, virgin female Sprague-Dawley rats were assigned to alcohol-fed, pair-fed, and chow groups based on weights. Alcohol animals were fed a liquid diet containing 35% ethanol-derived calories for 6 weeks. Pair-fed animals were matched to test animals on the basis of initial weight and fed an isocaloric diet equivalent to that consumed by the alcohol-matched animals on the previous day with alcohol replaced by maltose-dextrin. Right tibias were fixed and embedded in methyl methacrylate for sectioning. Sections (5 microm) were stained for cement lines and packets were measured using histomorphometric techniques on a BioQuant morphometric system. Alcohol-fed animals exhibited statistically significant decreases in the amount of bone surface containing active osteoblasts and a decrease in mean wall thickness. Osteocalcin values were significantly reduced from pair-fed levels and slightly, but not significantly, reduced from chow-fed animals.