Buparlisib (formerly BKM 120), an oral 2,6-dimorpholino pyrimidine derivative is a potent pan-PI3K inhibitor causing inhibition of PI3K downstream signaling including downregulation of p-Akt and p-S6R and apoptosis of cancer cells. Buparlisib is rapidly absorbed, has more than 90% bioavailability, good blood–brain barrier penetration and half-life of 40 h. Phase I trials have shown good disease control rate with tolerable toxicity profile at the recommended doses of 100 mg. The most common adverse events noted with buparlisib are rash, hyperglycemia, derangement of liver functions and psychiatric events. Several clinical trials with buparlisib alone or in combination with chemotherapy and targeted therapies are underway. Buparlisib has not yet been approved for regular use. Further randomized trials are required before buparlisib is approved for treatment of breast cancer.