One of the issues discussed by the late Shia jurists is the fact of componentness and not componentness of recommended elements of an obligatory action. Although the idea of componentness is concordant with common sense, but it is rejected by some scholars. They believe that the obligatory action is the dwelling of recommended elements. This article studies this issue with a critical analytical approach. This subject has effects in some jurisprudential issues like the rule of Tajawoz and the khelal (invalidators) of prayer. Although componentness of recommended elements of an obligatory action is a self-evident fact, but many late and contemporary scholars have objections to this idea. Analyzing the arguments of both sides, the writer has proven that the idea of componentness is acceptable.