  Metallicity gradients in the Sagittarius dwarf Galaxy (Sgr) are investigated
by using infrared photometric data from the 2MASS survey. To search for
metallicity effects, the giant branch in a field situated near the Center of
the Sgr is compared to the giant branch in a field situated near its southern
edge. The contamination of Sgr giant branch by foreground Galactic stars is
canceled by statistical subtraction of diagrams symmetrical in Galactic
latitude. After subtraction it is possible to reconstruct the Sgr giant branch
with excellent accuracy. The giant branch in the two fields have similar slopes
but are shifted in color. Even after correction for the differential reddening
between the fields, the shift in color between the branch remains, and is very
significant. This variation in the color of the giant branch corresponds to a
metallicity variation of about -0.25 Dex. The existence of a metallicity
gradient in Sgr may indicate that there are two different stellar population in
Sgr. One has low metallicity, and another one of higher metallicity has a
smaller spatial extension.
