Pegylated liposomal doxorubicin (PLD) is a liposomal formulation with a distinct pharmacokinetic profile characterized by an extended circulation time and a reduced volume of distribution. Biodistribution animal studies indicate preferential accumulation of PLD into various implanted mouse-human tumors, with an enhancement of liposomal drug tumor levels compared with free drugs. The extended circulation time of pegylated liposomes and their ability to extravasate through the leaky vasculature of tumors results in the enhanced delivery of liposomal drug and/or radiotracers to the tumor site in patients with cancer. In malignant effusions, Kaposi sarcoma skin lesions, and a variety of solid tumors there is evidence of selective tumor uptake detected by various methods. Pegylated liposomal doxorubicin has been approved for clinical use in a variety of neoplastic conditions because of its antitumor efficacy and unique safety profile with an impressive reduction of cardiac toxicity in comparison with conventional doxorubicin.