An oil-in-water nanoemulsion delivery system that includes at least one oil having a concentration of greater than or equal to 2% (w/w) of at least one polyunsaturated fatty acid, preferably of the omega-3 or omega-6 family, is disclosed. The delivery system further includes at least one emulsifier and also an aqueous phase. Preferably, one or more hydrophobic therapeutic, monitoring and/or diagnostic agents are dispersed in the oil phase. The nanoemulsions may optionally contain other conventional pharmaceutical aids such as stabilizers, preservatives, buffering agents, antioxidants, polymers, proteins and charge inducing agents. The invention also relates to a process for preparing the nanoemulsions and to their use in the oral, parenteral, opthalmic, nasal, rectal or topical delivery of hydrophobic therapeutic, monitoring or diagnostic agents.