The Notch signaling pathway regulates cell proliferation, apoptosis and cell fate decision. Recent preclinical and clinical evidence supports a pro-oncogenic function for Notch signaling in several solid tumors including breast and prostate cancer. Consequently, there is increasing interest in targeting Notch signaling therapeutically in cancer patients. Notch inhibitors, particularly gamma-secretase inhibitors, are being investigated as candidate cancer therapeutic agents. However, rational targeting of Notch signaling in cancer will require a systematic exploration of several areas that remain incompletely understood. Therefore, a clear understanding of the Notch signaling and its cross-talk with other signaling cascade will increase our ability to design rational combination regimens for cancer therapy.