The present invention is in the fields of drug delivery, cancer treatment and diagnosis and pharmaceuticals. This invention provides a method of making antibody- or antibody fragment-targeted immunoliposomes for the systemic delivery of molecules to treat and image diseases, including cancerous tumors. The invention also provides immunoliposomes and compositions, as well as methods of imaging various tissues. The liposome complexes are useful for encapsulation of imaging agents, for example, for use in magnetic resonance imaging. The specificity of the delivery system is derived from the targeting antibodies or antibody fragments.