A novel solvent-free, hot melt adhesive composition suitable for bonding a polar leather layer to a non-polar substrate is claimed. The composition comprises a block copolymer having at least one mono alkenyl arene polymer block and at least one controlled distribution copolymer block of at least one conjugated diene and at least one mono alkenyl arene, a hydrogenated tackifying resin, a resin compatible with the mono alkenyl arene blocks, optionally a functionalized poly(alkylene) resin, and stabilizers and/or auxiliaries. A process for bonding a polar leather layer to a non-polar substrate by application of the novel solvent-free, hot melt adhesive composition is also provided.