The interfacial behavior of third and fourth generations of hyperbranched polyesters (HBP3 and HBP4) with 32 and 64 hydroxyl terminal groups was studied. Higher adsorption amount under an identical adsorption condition was found for lower generation HPB3. The shape of HBP3 molecules within an adsorbed layer evolved from pancake with thickness below 1 nm for very low surface coverage to densely packed worm-like structures with thickness about 3 nm for the highest surface coverage. The molecules of the fourth generation, HBP4, hold stable close-to-spherical shape with a diameter of 2.5 nm over the entire range of surface coverage including both dense monolayers and isolated molecules. High intramolecular flexibility of HBP3 molecules as compared with constrained mobility of bulkier branches of HBP4 is considered to be responsible for this behavior, similar to regular dendrimer structures. A uniform monolayer with the thickness of 4.5 nm from an epoxy-functionalized hyperbranched polyester (EHBP) with a core functionalized by alkyl chains with secondary epoxy groups could be fabricated by melt grafting to a bare silicon surface. Such chemical architecture provides dual ability for both grafting to a solid substrate and an inducing surface functionality for the layer. Estimated 3-4 epoxy groups per molecule are located in the uppermost surface layer and provide residual functionality sufficient to graft another polymer layer with appropriate functionality. Grafted layers are extremely robust and sustain high compression and shear stresses while possessing high elasticity. The molecular structures of a series of HPs, HP-0, HP-10, HP-25, HP-50, HP-75 and HP-100, which have different percentage of substituted C17H35 branches, were identified by AFM, FTIR, GPC and LB technique. The number of experimentally substituted alkyl chains calculated from LB[Pi]-A isotherms were roughly in agreement with the theoretical values. AFM images showed there were some aggregate domains scattering on the surface of the LB deposited layers, and these domains demonstrated some pattern for higher surface pressure.