Pre-clinical data and recently published clinical data suggest a synergistic effect between lenalidomide and dexamethasone. We hypothesize that a combination of lenalidomide-dexamethasone can overcome rituximab resistance. To determine the response rate to lenalidomide and dexamethasone plus rituximab therapy in subjects with recurrent small B-cell non-Hodgkin lymphoma who have had lymphoma progression within 6 months of being treated with rituximab alone or with a rituximab-containing regimen, we propose initial treatment with both drugs for two 28-day treatment cycles (Part I). After response assessment following two cycles of lenalidomide-dexamethasone, patients will enter Part II of the study. In Part II, patients will receive lenalidomide-dexamethasone and rituximab to evaluate the potential reversal of rituximab resistance as measured by response to rituximab and progression-free survival following rituximab.