In the present study, 256 7-wk-old Japanese quail were randomly distributed into four experimental groups (64 birds per group) and given rations containing 0 (controls), 25, 50, or 100 (g aflatoxin B, (AFB1)/kg feed for 168 d. Each treatment consisted of four replicates of 16 quail. Egg production and individual egg weight were checked daily. Feed consumption and feed use were determined weekly. Eggs laid in the last day of each 28-d laying period were collected and subjected to individual analysis for specific gravity, Haugh units, shell thickness and percentage eggshell. Results showed that average egg production, feed use, and body weights were not affected (P > 0.05) by AFB1. However, feed consumption was lower (P < 0.05) for groups fed 50 or 100 microg AFB1/kg. Egg weight was significantly lower (P < 0.05) only for groups exposed to 50 and 100 microg AFB1/kg. Average egg specific gravity, Haugh units, and shell thickness were not affected (P > 0.05) by AFB1. Percentage eggshell was higher (P < 0.05) in the group fed the ration containing 100 microg AFB1/kg. Treatment associated lesions were observed only in the liver. Hepatic cell vacuolation with fatty infiltration was observed in all liver samples of quail fed AFB1-contaminated rations. Bile duct proliferation and trabecular disorder were found only in livers of quail on the 100-microg AFB1/kg treatment. Results indicated that chronic exposure to AFB1 at levels above 50 microg/kg could adversely affect quail performance, emphasizing the importance of controlling aflatoxin contamination in quail rations.