We report results from a search for massive and evolved galaxies at z \gtrsim 5 in the Great Observatories Origins Deep Survey ( GOODS ) southern field . Combining HST ACS , VLT ISAAC and Spitzer IRAC broad–band photometric data , we develop a color selection technique to identify candidates for being evolved galaxies at high redshifts . The color selection is primarily based on locating the Balmer–break using the K- and 3.6 \mu m bands . Stellar population synthesis models are fitted to the SEDs of these galaxies to identify the final sample . We find 11 candidates with photometric redshifts in the range 4.9 \leq z < 6.5 , dominated by an old stellar population , with ages 0.2 - 1.0 Gyr , and stellar masses in the range ( 0.5 - 5 ) \times 10 ^ { 11 } M _ { \odot } . The majority of the stars in these galaxies were formed at z > 9 and the current star formation activity is in all cases , except two , a few percent of the inferred early star formation rate . One candidate has a spectroscopically confirmed redshift , in good agreement with our photometric redshift . The galaxies are very compact , with half–light radii in the observed K - band smaller than \sim 2 kpc . Seven of the 11 candidates are also detected at 24 \mu m with the MIPS instrument on Spitzer . By itself , the 24 \mu m emission could potentially be interpreted as PAH emission from a dusty starburst at z \sim 2 - 3 , however , it is also consistent with the presence of an obscured AGN at z \gtrsim 5 . Indeed , for the z \gtrsim 5 solutions , all the MIPS detected galaxies , except two , have relatively high internal extinction . While we favor the obscured AGN interpretation , based on the model SED fits to the optical/UV , we define a ’ no–MIPS ’ sample of candidates in addition to the full sample . Results will be quoted for both samples . We estimate the completeness of the Balmer break galaxy sample to be \sim 40 % ( an upper limit ) . The comoving number density of galaxies with a stellar mass \gtrsim 10 ^ { 11 } M _ { \odot } , at an average redshift \bar { z } = 5.2 , is 3.9 \times 10 ^ { -5 } Mpc ^ { -3 } ( no–MIPS sample : 1.4 \times 10 ^ { -5 } Mpc ^ { -3 } ) . The corresponding stellar mass density is 8 \times 10 ^ { 6 } M _ { \odot } Mpc ^ { -3 } ( no–MIPS sample : 6.2 \times 10 ^ { 6 } M _ { \odot } Mpc ^ { -3 } ) . The estimated stellar mass density at \bar { z } = 5.2 is 2 - 3 % of the present day total stellar mass density and 20 - 25 % of the stellar mass density at z \sim 2 . If the stellar mass estimates are correct , the presence of these massive and evolved galaxies when the universe was \sim 1 Gyr old could suggest that conversion of baryons into stars proceeded more efficiently in the early universe than it does today .