Nile tilapia Oreochromis mlolicus were collected from a brackish pond near Lake Timsah (Suez Canal); the energy content of the somatic tissues (muscles) and gonads has been determined during the spawning-season (March-June 2003) using the wet dichroinate oxidation method. The gonadal relative energy content (Jmg"1) of the gonad of both males and females exhibited the same pattern of increasing throughout the maturity staees. There wer* no marked differences in the relative energy content of the fish muscles. The absolute energy content (J) of the somatic tissues of males and females increased gradually with the increase of length (cm).