The 27th World Science Fiction Convention, also known as St. Louiscon, was held August 28–September 1, 1969, at the Chase Park Plaza Hotel in St. Louis, Missouri, United States, under the auspices of OSFA, the Ozark Science Fiction Association.
Konvensi Fiksi Ilmiah Sedunia ke-27, juga dikenal sebagai St. Louiscon, diadakan pada 28 Agustus–1 September 1969, di Chase Park Plaza Hotel, St. Louis, Missouri, Amerika Serikat, di bawah bimbingan OSFA, Asosiasi Fiks Ilmiah Ozark.