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We report on progress and future plans for calculating kaon weak matrix elements for ǫ ′ /ǫ using staggered fermions. The first goal of this project is to provide a check of the results (ǫ ′ /ǫ < 0) obtained using quenched Domain Wall fermions (DWF) by the CP-PACS [1] and RBC [2] collaborations. The second goal is to extend the work to dynamical simulations, since quenching is likely one of the main systematic errors in present calculations [3]. The third goal is either to find a window for new physics or to confirm the standard model, when our numerical results are compared with the observed values. Staggered fermions are appropriate for this purpose, because they preserve enough chiral symmetry to prevent composite operators from mixing with wrong chirality operators and to protect quark mass from additive renormalization, which is essential to calculate ǫ ′ /ǫ. They have the advantages over DWF of requiring less CPU time and dynamical simulations are already possible with relatively light quark masses. By construction , staggered fermions carry four degenerate flavors (also called " tastes "). They allow large flavor changing quark-gluon interactions, which makes it impractical to non-perturbatively determine matching constants for operators of our interest. Another disadvantage is that the unim-proved action and operators receive large pertur-bative corrections at one loop and have large scaling violations of order a 2. Both of these disadvantages can be alleviated by improving staggered fermions using smeared links. Flavor symmetry breaking in the pion spectrum is significantly reduced with such links [4,5]. Our project has progressed through the following steps. 1. We calculated the current-current diagrams for the gauge-invariant unimproved staggered fermions at one loop [6], which provided a complete set of perturbative matching formula for ǫ ′ /ǫ, combined with existing results for penguin diagrams [7]. 2. We performed a numerical study on ǫ ′ /ǫ using the Columbia QCDSP supercomputer [3]. Using the matching formula given in [6,7], we constructed fully one-loop matched gauge-invariant operators. As expected, we found large perturba-tive corrections for B 6 , so that we cannot quote quantitative results for this although the statistical uncertainty is under control. An unexpected result was that different quenched transcriptions of the continuum operators on the lattice (proposed by Golterman and Pallante [8]) lead to substantially different values for B 6 [3]. This indicates a large quenching uncertainty and deserves further study. 3. The …