Abstract: A description is given of a process for reducing the agglomeration tendency of hydrates within a fluid incorporating at least water and hydrocarbons, liable to form hydrates, under conditions where said hydrates may form, characterized in that into said fluid is incorporated an alkylene oxide-based hydrosoluble polymer or copolymer containing at least one --(OR)--.sub.n sequence, in which R represents a hydrocarbon group having 2 or 3 carbon atoms and n represents the average degree of polymerization of said sequence, at least one of the --(OR)--.sub.n sequences being an ethylene polyoxide sequence, associated with a thermodynamic inhibitor of the formation of hydrates, e.g. an alcohol or a glycol. This process is particularly appropriate for the case where the fluid to be treated contains a high proportion of water, e.g. more than 30% by weight. The presence of salts in the water can at least partly dispense with the addition of alcohols or glycols.