The hydrocracking of high-density polyethylene (HDPE) mixed with vacuum gas oil (VGO) (20 wt% HDPE) has been investigated with the aim of assessing this valorization strategy to obtain products suitable to be used as commercial fuel blending streams. The runs have been conducted in a batch reactor at: 400-440 degrees C; 80 bar; catalyst to feed ratio, 10 gcat gfeed(-1); and reaction time, 2 h. Using three different catalysts, PtPd/Y, NiW/Y and NiMo/SA, the effect of the temperature and the composition of the products have been analyzed, comparing obtained results in the hydrocracking of VGO with those obtained for the HDPE/VGO blend. The products distribution has been quantified determining the yields of different lumps, defined according to their boiling point range: gas, naphtha, light cycle oil, heavy cycle oil and coke. The concentration of the families of compounds has been also determined: paraffins, olefins, naphthenes and aromatics (mono-, di-and poly-). Obtained results reveal that the addition of HDPE to the VGO is a promising way to valorize the HDPE, improving the conversion of VGO while producing interesting valuable products. Indeed, at 440 degrees C and with PtPd/Y catalyst total conversion of HDPE has been obtained, with a of 31.8 wt%.