Although differential object marking (DOM) has been studied from a multitude of perspectives, research into the types of variation it allows in closely related languages is still needed. This article examines DOM from the point of view of (micro)variation, focusing on two genetically related languages, namely, standard Spanish and Romanian. Both identities and points of divergence are discussed in detail and argued to result from a morphosyntactic parameter in the realm of differential marking. Following López [López, Luis. 2012. Indefinite Objects Scrambling, Choice Functions and Differential Marking. Cambridge, MA: MIT Press], the Spanish special marker signals certain types of nominals which undergo short scrambling in order to have Case licensed. In Romanian, however, DOM is equated with an additional operation beyond the valuation of Case.