This study was conducted to the effect of chloramhenicol on the e gig production of the laying hens and the residue levels in the eggs. Laying hens in four groups of 30 were fed on a diet containing chloramphenicol 0 ppm (group I), 20 ppm (group II) and 40 ppm (group III) for two mounths and 400 ppm (group IV) as a therapoutic dose for 5 days.

Chloramphenicol did not effect on egg yield, egg weight, feed intake, and fed efficiency ratio.

The residue of the chloramphenicol in the eggs were determined by uising HPLC. Residues of the chloramphenicol can be routinly quantitated by this method at 2 ppb with 80-90 % recovery.

No residue of chloramphenicol in the eggs from the group II was detected. But 5-20 ppb residue were faund in the eggs from group III. Increasing level of residues (58-197) were in the eggs from group IV in the first five days. Then the levels of residues decreased and were not detected on the day 30 after withdrawal of the drug.