1. Eggs from a broiler breeder flock between 25 and 29 weeks of age were dipped into solutions of various concentrations of ascorbic acid (AA) for up to 2 min, in order to evaluate its effects on eggshell conductance (EC), amniotic fluid pH, albumen height and pH, embryonic weight and hatchability. 2. Three experiments were conducted and the following treatments were used: control, non-dipped (CND); control, water-dipped (CWD); 10 g AA/l (AA1); 20 g AA/l (AA2) and 30 g AA/l (AA3). Measurements of EC before and after dipping were made in experiments 1 and 2 in eggs from hens at 25 and 27 weeks of age, respectively. Albumen height and pH were measured after dipping the eggs in experiment 2. In experiment 3, egg weight loss, embryonic weight and amniotic fluid pH at 14 d of age, hatchability percentage (HP), and embryonic mortality were measured in eggs from hens at 29 weeks of age. 3. AA treatment of eggs and dipping period of time (1, 1.5 and 2 min) increased EC of eggs from hens at 25 and 27 weeks of age. 4. AA3 treatment for 2 min reduced albumen height and increased albumen pH of eggs when compared with the CND treatment in eggs from hens at 27 weeks of age. 5. HP of AA1-treated eggs from hens at 29 weeks of age was higher than that of the CND treatment. AA2 and AA3 treatments of eggs reduced HP and increased the percentage of non-pips when compared with any of the other treatments. 6. AA2 and AA3 treatments of eggs increased egg weight loss when compared with the control treatments (CND and CWD). Dipping treatment did not influence amniotic fluid pH or embryo weight expressed as a percentage of initial egg weight. 7. It is concluded that dipping hatching eggs into AA solution increased EC of eggs. Dipping eggs into 10 g AA/l for a period of 2 min increased HP in eggs from hens at 29 weeks of age, although this was not associated with a significant increase in egg weight loss.