Several foci of lobomycosis among Colombian Amer Indians population were described in the Casanare region of Colombia, near the Orinoco river on the Colombian-Venezuelan border. This paper reports 16 new patients. The prevalence of Lobo's disease was 8.5% in the Amoruas tribe. Nodular lesions were located on the elbow, scapular and lumbar regions, knees, feet and legs. Leg lesions were especially numerous, were confluent and tended to ulcerate. All cases were confirmed histologically. Two Negro patients were also described. The cases bring the total number of confirmed patients with lobomycosis in Colombia to 41. Twenty-five of these were Amer Indian patients from tribes living in the Orinoco and Amazon basins of the country.