We found evidence of a symbiotic relationship between Fusarium solani (Martius) and Hypothenemus hampei (Ferrari). Females of H. hampei colonizing coffee beans infested with F. solani produced significantly more progeny than those colonizing sterile beans. Beans infested by F. solani had significant amounts of ergosterol, which was not present in sterile beans. Fecundity and survival of H. hampei was positively correlated with the content of ergosterol in their diet. Other evidence of symbiosis includes the presence of F. solani spores caught in cuticular protuberances, known as asperites, on the pronotal area of female H. hampei. The asperites are flat and arranged in a radial pattern presenting a pronounced inclination directed to the center of this radial pattern which originates at a protuberance on the pronotal area. The asperites appear to increase the chances of fungal deposition on the pronotum when female beetles bore into infested coffee beans. The existence of a mutualistic association between H. hampei and F. solani and the role of the pronotal structures as primitive mycangia are discussed.