A process for making a hydrophobic isocyanate based organic aerogel/xerogel/cryogel having water repellent properties, a water contact angle > 90° and comprising a cross-linked porous network structure made of polyurethane and/or polyisocyanurate and/or polyurea and hydrophobic compounds covalently bonded within the porous network, said process comprising the following steps: a) Providing a polyisocyanate composition selected from aliphatic isocyanates, aromatic isocyanates or isocyanate ended prepolymers made by reaction of an excess of a diisocyanate or higher functionality polyisocyanate with a hydroxyl ended polyester or hydroxyl ended polyether, and b) Optionally providing an isocyanate-reactive composition, and c) Optionally providing at least one catalyst compound promoting a polyurethane and/or polyurea and/or polyisocyanurate formation (trimerization), and d) Providing a solvent composition, and e) Providing hydrophobic compounds having a solubility in water <10g/L at 20°C, at least one isocyanate-reactive group and no isocyanate groups, said compounds being different from b) and suitable to impart hydrophobicity to the aerogels/xerogels/cryogels obtained in step j), and f) Optionally providing further additives, and then g) Combining the compositions/compounds a), d), e) and optionally b) and/or c) and/or f) to form a gel comprising a porous cross-linked polyurethane and/or polyurea and/or polyisocyanurate network having hydrophobic compounds covalently bonded in the network, this step referred to as "gelling" step, and then h) Optionally removing unreacted species, and then i) Optionally exchanging solvent, and then j) Drying (solvent removal) the porous network in order to obtain the hydrophobic isocyanate based organic aerogel/xerogel/cryogel having a water contact angle >90°, preferably >150° using the drop shape method of contact angle measurement. a) Providing a polyisocyanate composition selected from aliphatic isocyanates, aromatic isocyanates or isocyanate ended prepolymers made by reaction of an excess of a diisocyanate or higher functionality polyisocyanate with a hydroxyl ended polyester or hydroxyl ended polyether, and b) Optionally providing an isocyanate-reactive composition, and c) Optionally providing at least one catalyst compound promoting a polyurethane and/or polyurea and/or polyisocyanurate formation (trimerization), and d) Providing a solvent composition, and e) Providing hydrophobic compounds having a solubility in water <10g/L at 20°C, at least one isocyanate-reactive group and no isocyanate groups, said compounds being different from b) and suitable to impart hydrophobicity to the aerogels/xerogels/cryogels obtained in step j), and f) Optionally providing further additives, and then g) Combining the compositions/compounds a), d), e) and optionally b) and/or c) and/or f) to form a gel comprising a porous cross-linked polyurethane and/or polyurea and/or polyisocyanurate network having hydrophobic compounds covalently bonded in the network, this step referred to as "gelling" step, and then h) Optionally removing unreacted species, and then i) Optionally exchanging solvent, and then j) Drying (solvent removal) the porous network in order to obtain the hydrophobic isocyanate based organic aerogel/xerogel/cryogel having a water contact angle >90°, preferably >150° using the drop shape method of contact angle measurement.