Picosecond time-resolved fluorescence depolarization was measured at high pressures for p-terphenyl (PTP) in n-octane and 1-butanol. The rotational reorientation time (tau(R)) was deduced from these measurements and studied as a function of solvent viscosity. The viscosity dependence of tau(R) was compared with the results predicted by hydrodynamic models. A faster deviation than predicted from the modified SED slip hydrodynamic model was observed,