A review of the literature regarding bartonellosis or Carrion's disease in Colombia and Ecuador is presented, together with observations made by the author in areas of both countries from which the disease has been recorded. There is evidence from pre-Columbian artifacts that verruga peruana, the cutaneous form of the disease, was present in Ecuador at least 1,000 years prior to the arrival of Europeans. These artifacts were discovered in the coastal province of Manabi, a low-lying area very different from the high Andean valleys of Peru with which bartonellosis is normally associated. Most of the cases recorded in recent years from this coastal area. The disease does not appear to have occurred in Colombia before the 1930s and only one case has been reported during the past 40 years. The possibility of many more subclinical cases being present in both Ecuador and Colombia is discussed, together with the possibility that the acquired immunodeficiency syndrome epidemic will reveal a higher prevalence among the inhabitants of endemic areas than previously suspected. Although the suspected vector of Bartonella bacilliformis, the sand fly Lutzomyia verrucarum, has not been recorded from Ecuador or Colombia, related species are present in endemic areas and may be involved in transmission.