The properties of Langmuir layers made up of a series of derivatized fulleropyrrolidines featuring hydrogenated and fluorinated acyl chains have been investigated, focusing on their ability to form a monomolecular layer. We have found that compounds with hydrocarbon chains form floating films on the subphase whose thickness depends on the concentration of the spreading solution as observed in pure C-60. On the contrary, the fluorinated derivative gives rise to monomolecular layers irrespective of the concentration values.