The swelling of densely grafted planar homo- and copolymer brushes in solvent vapors was studied by the dissipative particle dynamics method. It is shown that the distribution of the solvent inside the polymer film is inhomogeneous with the explicit maximum at the polymer–vapor interface. The value of the maximum does not depend on the grafting density and is mainly defined by the concentration of solvent vapors. At the same time, the distribution function of the free ends in homopolymer brush swollen in vapors of a good solvent is closer to the respective function in dry (solvent-free) brush: it has a rather narrow maximum at the upper border of the brush. In case of copolymer brushes, the swelling in vapors of a selective solvent can be accompanied by separation, the character of which is defined by the sequence of polymer segments (random or gradient) and also by the mean fraction of the segments of different types. The distribution function of free ends in the copolymer brush is calculated.