Pemphigus and lupus erythematosus are both B-cell-mediated autoimmune diseases, dependent on autoreactive CD4+ T lymphocytes to modulate autoimmune B-cell response. Many forms of pemphigus have been reported to occur in association with systemic lupus erythematosus (SLE) as well as other autoimmune diseases. However, it remains unclear whether this association occurs because of a shared immunopathogenesis or the coexistence may be coincidental. We hereby present a case report of discoid lupus erythematosus and paraneoplastic pemphigus associated with marginal zone lymphoma in a 54-year-old Thai man who had persistent oral erosions for 1 year together with generalized polymorphic cutaneous eruptions for 2 months. Simultaneous occurrence of paraneoplastic pemphigus and discoid lupus erythematosus without SLE has never been reported in the same individual. Hydroxychloroquine, immunosuppressive agents including prednisolone and azathioprine together with chemotherapy were given to treat these conditions.