We report a case of visceral leishmaniasis in a human immunodeficiency virus (HIV)-infected 37-year-old Thai fisherman who presented with nephritonephrotic syndrome, fever, anemia, and thrombocytopenia. Bone marrow biopsy revealed many amastigotes within macrophages. Kidney biopsy showed membranoproliferative glomerulonephritis. Polymerase chain reaction (PCR) and nucleotide sequence analysis of the internal transcribed spacer 1 of the small subunit ribosomal RNA gene in blood and kidney biopsy specimens showed Leishmania species previously described in a Thai patient with visceral leishmaniasis. Only four autochthonous cases of leishmaniasis have been reported in Thailand since 1996. To the best of our knowledge, this is the first report of autochthonous visceral leishmaniasis in an HIV-infected Thai. With an increasing number of patients with autochthonous leishmaniasis in association with the presence of potential vector, it remains to be determined whether this vector-borne disease will become an emerging infectious disease in Thailand.