A theory of swelling of macromolecular networks at least partially accounting for excluded volume of macromolecules is developed. For tetrafunctional crosslinkages the following relationship results: $$—[\ln(1—v_{2}) + v_{2} + \chi_{1} v^{2}_{2}] = V_{1} \frac{\nu}{V_{0}} \left( \frac{5}{3} v^{1/3}_{2} - \frac{7}{6} v_{2} \right)$$ where $\mathcal{X}_{1}$ is the polymer-solvent interaction parameter, $v_{2}$ the equilibrium volume fraction of polymer in the gel, $V_{1}$ the molar volume of solvent and $\frac{\nu}{V_{0}}$ the numer of moles of chains per volume unit.