Solubility of light fullerenes (C₆₀ and C₇₀) in n-nonane was investigated in the ranges of pressure form 0.1 MPa up to 100 MPa and temperature from 298.3 K to 353.3 K. Under isothermal conditions, the solubility, expressed as weight fraction of the fullerene in the solution, increases monotonously with increasing pressure. At ambient pressure, we have found that the temperature dependence of the solubility of C₆₀ in n-nonane is non-monotonic: the solubility diagram consists of two branches corresponding to crystallization of different solid phases and one invariant point corresponding to simultaneous saturation of both phases. At 0.1 MPa, the solubility diagram of the binary system C₇₀ – n-nonane in the analysed temperature range consists of only one branch corresponding to crystallization of non-solvated C₇₀.