The invention provides a method of inducing an immune response against malaria in a mammal. The method comprises intramuscularly administering to a mammal a composition comprising a pharmaceutically acceptable carrier and either or both of (a) a first adenoviral vector comprising a nucleic acid sequence encoding a P. falciparum circumsporozoite protein (CSP) operably linked to a human CMV promoter, and/or (b) a second adenoviral vector comprising a nucleic acid sequence encoding a P. falciparum apical membrane antigen 1 (AMA-1) antigen operably linked to a human CMV promoter.