Some scholars explain the major anatomical characteristics that differentiate Homo erectus from its predecessor, Homo habilis, as the result of Homo erectus being adapted to use fire for cooking and other tasks. However, many scholars contend that the evidence of fire in Homo erectus sites is very scant and is not convincingly anthropogenic. This study presents a methodology to evaluate the evidence of fire associated with the 1.5-million-year-old Homo erectus site FxJj20 AB, Koobi Fora, Kenya. The evidence is in the form of thermally altered lithics, soil aggregates, and bone fragments identified using visual inspection and Fourier transform infrared spectroscopy (FTIR). We conducted high-resolution excavation focused on the recovery and high-resolution mapping of large and small finds (<2 cm). ArcGIS spatial analysis and soil micromorphology were used to assess whether the evidence of fire at the site has a natural or anthropogenic origin. Preliminary results indicate that the spatial pattern of heated and unheated archaeological material is not inconsistent with prehistoric anthropogenic fire features found in archaeological sites of Europe and West Asia.