Streptococcus pseudoporcinusis a nonmotile Gram-positive, catalase, and benzidine negative, arranged in short chains, isolated from the genitourinary tract group BStreptococcus.S. pseudoporcinuswas also identified from blood, urine, skin, cervical area, wounds, rectum, and placenta samples. Two cases of infective endocarditis have been reported in the literature. Based on these data, the identification of a case ofS. pseudoporcinusinfective endocarditis associated with spondylodiscitis in a patient with undiagnosed systemic mastocytosis until the age of 63 years is unusual. Two sets of blood specimens were collected, and both sets were positive forS. pseudoporcinus. Transesophageal echocardiography revealed, multiple vegetations on the mitral valve. A lumbar spine MRI revealed L5-S1 spondylodiscitis that associates prevertebral and right paramedian epidural abscesses with compressive stenosis. The performed bone marrow biopsy, and cellularity examination revealed 5–10% mast cells in the areas of medullary tissue, an aspect that is suggestive of mastocytosis. Antibiotic therapy was initiated, under which the patient presented intermittent fever. A second transesophageal echocardiography revealed a mitral valve abscess. A mitral valve replacement with a mechanical heart valve device through a minimally invasive approach was performed, with a favorable evolution under treatment.S. pseudoporcinuscan be responsible for infectious endocarditis in certain immunodepressed cases, but also in a profibrotic, proatherogenic field, as shown by the association with mastocytosis in the presented case.