This article discusses the obligation to take precautions in attack. It uses as a case study Operation “Neptune Spear”, whose goal was to kill or capture Osama Bin Laden in Pakistan in 2011, and which was regarded as a resounding success. The author assumes the position that the LOAC is the relevant paradigm for analyzing the legality of the operation and that Osama Bin Laden was a lawful target. Based on these assumptions, he analyzes some of the customary rules of precautions in attack and their possible application to the operation. In particular, this article discusses the scope of the duty to take constant care to spare the civilian population in the planning and execution of a military operation. It also studies the requirement to verify that an attack is lawful, and the obligations for those planning or executing the attack, with regard to the choice of means and method.