The invention relates to a hydrocarbon hydroconversion catalyst comprising a carrier based on refractory oxide, a metal of the group VIII, and a metal of the group VIB. Said catalyst is characterised in that it also comprises at least one organic compound selected from the alkene diols of formula (I) wherein R1 represents a C2-10 alkenylene group, preferably C2-4 alkenylene, a C6-18 arylene group, or a C7-18 alkylene-arylene group, and each R2 independently represents a hydrogen atom or a C1-18 alkyl group, a C1-18 alkenyl group, a C6-18 aryl group, a C3-8 cycloalkyl group, or a C7-20 alkylaryl or arylalkyl group, or the two groups R2 together form a divalent C2-18 group, the carbonated chain of the R2 groups containing or carrying at least one heteroatom selected from S, N and O. The invention also relates to a method for preparing one such catalyst, and to the use of said catalyst for hydrotreatment or hydroconversion.