In Colombia, it is very common to find informal street grills selling charcoal-roasted foods such as “arepas” (corn tortillas), meats, bananas, corn, etc. This informal economy represents the livelihood of many families. In these stalls, workers are exposed for 5 to 9 hours a day to particulate matter emitted from their grills. This paper presents a characterization of ultrafine particles from some charcoal street grills in the city of Armenia (Colombia), in order to determine whether their workers are at risk to their health. A total of two different samples were taken in two street charcoals grills. Particle distribution and elemental chemical analysis was determined by SEM and EDS. Results show the presence of ultrafine particles in both samples.