In this study, flexible and open cell polyurethane foams were formulated and chemically modified with organosilane to be used as a sorbent system for oil spill cleanup. Six polyurethane foams with different densities and three oil types with different viscosities were investigated. Moreover, sorbents were characterized based on their surface modification and sorption capacities. The main results indicated that the surface treatment on the solid fraction of the foam was effective, observing by the contact angle, thereby increasing the hydrophobicity of the samples. Cell morphology and foam density directly affect the sorption capacity of foams. Foams with high densities are indicated for oils with low viscosity, and foams with low densities are indicated for viscous oils. The oil sorption capacity also depends on oil viscosity (and temperature).