In this seminar I will present results of our ground-based photometric survey of trans-Neptunian objects (TNOs) and centaurs, which is part of the PhD project about Photometric Studies of Small Bodies of the Solar System, TNOs are considered leftovers of the proto solar nebula, while the Centaurs are a transient population of TNOs located between the orbits of Jupiter and Neptune, thus their physical and dynamical properties provide important information for the theories of Solar System formation. Among the techniques used to study such objects, photometry is the less expensive one (in terms of observing time). Photometric studies allow to obtain information of physical properties of TNOs via absolute magnitudes and colors. Our goal was to construct phase curves in two filters, V and R, of a large TNO sample: we obtained absolute magnitudes (H) and phase coefficients (β), to study possible relations between them and other physical parameters (orbital elements, sizes, and albedos). We obtained absolute magnitudes, 114 in V filter and 113 in R filter. From the latest, we get phase curves in both filters for 106 objects. From the search for correlations we found a strong anti-correlation between H V − H R and ∆ β = β V − β R , which is probably related to the surface structure.