Primary central nervous system lymphoma (PCNSL) is a rare subtype of extranodal non-Hodgkin lymphoma (NHL) located in the craniospinal axis (affecting CNS, meninges and eye) without evidence of a systemic primary tumor. CNS lymphomas are typically high grade, large cell lymphomas; low grade CNS lymphomas are rare. We encountered a case of 48-year old patient with recurrent episodes of seizures, weakness of bilateral extremities and memory loss. On MRI and CT scan, a 2.0 cm area of ill-defined enhancement with associated edema was present in the left frontal subcortex. The biopsy revealed an infiltrate of small lymphocytes expressing pan B-cell markers and an immunoprofile consistent with an extranodal marginal zone B cell lymphomas of mucosa associated lymphoid tissue (MALT). Clonal rearrangement was demonstrated by PCR analysis. Subsequently, the patient was treated with radiation therapy and responded well, with decrease in the size of the lesion. He is alive and well for 1 year and 3 months up to the date of this report.