We propose a robust, unified framework, in which the similar baryon and dark matter cosmic abundances both arise from the physics of weakly interacting massive particles (WIMPs), with the rough quantitative success of the so-called “WIMP miracle.” In particular the baryon asymmetry arises from the decay of a metastable WIMP after its thermal freeze-out at or below the weak scale. A minimal model and its embedding in R-parity violating supersymmetry are studied as examples. The new mechanism saves R-parity violating supersymmetry from the potential crisis of washing out primordial baryon asymmetry. Phenomenological implications for the LHC and precision tests are discussed.