Despite benefits of systemic chemotherapy in breast cancer treatment, several patients with early-stage breast cancer will develop metastatic breast cancer (MBC). Doxorubicin is among the most active agents against MBC. However, the use of doxorubicin is related to some life-threatening side effects including cardiotoxicity. Many efforts were made to lessen the side effects of doxorubicin and improve its efficacy. Pegylated liposomal doxorubicin (PLD) is a product claimed to achieve these two objectives because of its different pharmacokinetic profile. The aim of this study was to determine the side-effect profile of PLD in MBC through a systematic review of phase II clinical trials. A literature search in PubMed-MEDLINE was performed using terms covering nano-based pharmaceutical systems, 'breast cancer' and 'doxorubicin'. Articles were evaluated according to the inclusion criteria. Reported hematological and non-hematological side effects were categorized. Out of 718 articles that were initially identified, 8 were in accordance with the inclusion criteria. We found that the most important side effects of PLD were skin toxicity and mucositis, but the proportion of patients who showed grade III and IV of these side effects was relatively low. On the other hand, the occurrence of cardiotoxicity, the most important problem with doxorubicin, was considerably reduced in patients treated with PLD. Although PLD has demonstrated a lower toxicity profile than conventional anthracyclines, it has also new side effects. However, it seems that the reduced cardiotoxicity of PLD has made it a more appropriate option in patients with MBC, especially in those with risk factors for cardiac diseases.