Studying GMCs in galaxies using CO emission requires spatial resolutions higher than 30-40 pc. It will be possible to extend studies such as ours to a few tens of Mpc soon, with the advent of ALMA and CARMA arrays in the southern and northern hemispheres respectively. These instruments will provide angular resolutions of 0.1-1 arcsec in millimeter and sub-millimeter CO emission, corresponding 5-50 pc at 10 Mpc and will provide unprecedented details of physical conditions in GMCs in galaxies. The work described in this chapter should be just the beginning of extragalactic GMC studies.