We have determined the Ti and O components of the rutile TiO$_2$ valence band using the method of site-specific x-ray photoelectron spectroscopy. Comparisons with calculations based on pseudopotentials within the local density approximation reveal the hybridization of the Ti 3$d$, 4$s$, and 4$p$ states, and the O 2$s$ and 2$p$ states on each site. These chemical effects are observed due to the large differences between the angular-momentum dependent matrix elements of the photoelectron process.