Two experiments were conducted to determine the influence of dietary sodium and chloride on eggshell quality of leghorn hens. In the first, hens were fed for 4 wk diets containing three levels of calcium (2.0, 2.8, and 3.5%) and two levels of chloride (.25 and .86%) in a factorial arrangement of treatments involving four replicates of five hens/treatment. Neither chloride nor calcium significantly affected hen-day egg production or egg weight (P greater than .05); however, chloride decreased feed consumption and calcium increased body weight gain (P less than .05). Interactions of calcium and chloride were significant for eggshell strength (P less than .06) and eggshell thickness (P less than .05). Chloride decreased these measures of eggshell quality only for hens receiving 2.0% calcium, and calcium improved both measures only for hens receiving .86% chloride. Chloride decreased blood bicarbonate concentration and base excess (P less than .05), but did not affect blood pH and pCO2 (P greater than .05). The effect of dietary sodium and chloride on eggshells of hens receiving 2.0% dietary calcium was determined in a second experiment. Seven diets ranging from .18% sodium and .94% chloride to .76% sodium and .24% chloride were provided for 4 wk to five replicates of five hens/treatment. Dietary sodium and chloride levels did not affect hen-day egg production or egg weight (P greater than .05). Increasing the proportions of sodium relative to chloride decreased food intake but increased eggshell strength and thickness (P less than .01) and increased blood pH (P less than .05), bicarbonate concentration (P less than .01), and base excess (P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)