The invention is related to an oncolytic adenovirus that comprises a sequence encoding a hyaluronidase enzyme inserted in its genome. This adenovirus spreads more efficiently in the tumour mass and therefore the oncolytic effect is increased. Injecting the oncolytic adenovirus of the invention endovenously, tumour volume regressions are obtained. Therefore the oncolytic adenovirus of the present invention is useful for the treatment of a cancer or a pre-malignant state of cancer.