Mucosa-associated lymphoid tissue (MALT) lymphoma (ML) is a type of non-Hodgkin's lymphoma involving MALT, commonly the stomach or salivary glands, although virtually any mucosal site can be affected. ML originates from B cells in the marginal zone of MALT, and is also called extranodal marginal zone B cell lymphoma. It is a slow-growing cancer that usually responds well to treatment. A 59-year-old female presented with a 1-day history of quadriparesis and dysarthria. Up arrival at the hospital, motor power in the right upper and lower extremities was grade 3/5 according to the Medical Research Council scale, while that in the left leg was 4/5. The patient had been diagnosed with gastric ML 1 year prior, and had received antibiotics during the previous 2 weeks. The emergency magnetic resonance imaging of the brain performed at the time of presentation showed multifocal embolic infarction in the cerebral hemisphere bilaterally, which did not have a cardiac origin. Magnetic resonance angiography revealed no stenotic or occlusive lesions. Secondary prophylaxis with daily administration of 300 mg aspirin was prescribed. The patient was discharged with residual right hemiparesis 2 weeks after the onset of symptoms. Herein, we present a rare case of multifocal cerebral infarction in a gastric ML patient.