Most existing modular model checking techniques betray their hardware roots: they assume that modules compose in parallel. In contrast, feature-oriented software designs, which have proven very successful in several domains, are sequential in the simplest case. Most interesting feature-oriented designs are really quasi-sequential compositions of parallel compositions. These designs demand and inspire new verification techniques. This paper presents algorithms that exploit the software’s modular decomposition to verify feature-oriented designs. Our technique can verify most properties locally in the features; we also characterize when a global state space construction is unavoidable. We have validated our proposal by testing it on several designs.