We present the results of the first analysis of high dispersion spectra of four red HB stars in the metal rich globular cluster NGC 6528 , located in Baade ’ s Window .
We find that the mean [ Fe/H ] for NGC 6528 is +0.07 \pm 0.01 dex ( error of the mean ) , with a star-to-star scatter of \sigma = 0.02 dex ( 4 stars ) , although the total error is likely to be larger ( \sim 0.1 dex ) due to systematic errors related to the effective temperature scale and to model atmospheres .
This metallicity is somewhat larger than both the mean abundance in the galactic bulge found by McWilliam & Rich ( 1994 ) and that found in our previous paper for NGC 6553 .
However , we find that the spectra of clump stars in NGC 6528 and NGC 6553 are very similar each other , the slightly different metal abundances found being possibly due to the different atmospheric parameters adopted in the two analyses .
Since the present analysis is based on higher quality material , we propose to revise our previous published metal abundance for NGC 6553 to [ Fe/H ] = -0.06 \pm 0.15 .

For NGC 6528 we find excesses for the \alpha -process elements Si and Ca ( [ Si/Fe ] =+0.4 and [ Ca/Fe ] =+0.2 ) , whereas Mn is found to be underabundant ( [ Mn/Fe ] = - 0.4 ) .
We find a solar abundance of O ; however this is somewhat uncertain due to the dependence of the O abundance on the adopted atmospheric parameters and to coupling between C and O abundances in these cool , metal-rich stars .
Finally , we find large Na excesses ( [ Na/Fe ] \sim + 0.4 ) in all stars examined .