Abstract: The present invention relates to oncolytic adenoviruses with functional deletions of immunodominant T-cell epitopes of adenovirus proteins, as well as to methods of using the oncolytic adenoviruses for the treatment of diseases, such as cancer. The oncolytic adenoviruses may also contain one or more heterologous nucleic acid sequences each encoding a tumor antigen or epitope. The oncolytic adenoviruses may also contain other mutations and insertions of DNA sequences used to confer selectivity and antitumor potency. The invention has application in the field of cancer therapy.