[citation needed] Sagnotti's main contribution to physics is perhaps the analysis of the 2-loop divergences in Einstein's theory of General Relativity.

[11][12] He has worked extensively on higher spins, arriving at a geometric formulation of their free field equations in terms of higher-spin curvatures.

[13] More recently, Sagnotti has been working on the proposal of a possible link between "brane supersymmetry breaking",[14][15][16][17] and the onset of the inflationary phase, and on the exploration of some of its possible imprints on the CMB,[18] in particular, the proposal that the low value of the CMB quadrupole[19] and a first peak for l ~5[20] be a manifestation of the onset of the inflationary phase.

Sagnotti received the Carosio Prize from the University of Rome “La Sapienza” in 1979, a Miller Fellowship from U.C.

Berkeley in 1984, shared with Massimo Bianchi the 1994 SIGRAV Prize of the Italian Society for General Relativity and Gravitation,[21] and received the Margherita Hack Prize for Science in 2014 for his work on the quantization of gravity and a Humboldt Research Award in 2018.