Introduction: dust mites are an important source of allergens. Barranquilla has the highest prevalence of allergic asthma and rhinitis in the Colombian Caribbean, but little is known about these variables in Santa Marta. This is the reason why research was conducted into the prevalence and density of the acari Blomia tropicalis, Dermatophagoides pteronyssinus and Dermatophagoides farinae in Barranquilla and Santa Marta, two cities in Colombia. Objective: gather updated information about house mites associated with allergic respiratory diseases such as asthma and rhinoconjunctivitis in Barranquilla and Santa Marta, where their prevalence is high. Methods: dust samples were collected between May and September 2011. The mites were isolated and identified under the microscope. Total density was expressed as mites per dust gram. Fifty samples were examined in the city of Barranquilla and 52 in Santa Marta. Results: in Barranquilla, the most prevalent species was Blomia tropicalis (92%), followed by Dermatophagoides pteronyssinus (78%) and Cheyletus sp (36%). In Santa Marta, the most prevalent species was Dermatophagoides pteronyssinus (54%), followed by Blomia tropicalis (46%) and Dermatophagoides farinae (33%). Other mites of medical interest were Euroglyphus maynei, Demodex sp andGohieria fusca. A density > 500 mites per dust gram was found in 42% of the samples from Barranquilla and 15% from Santa Marta. Blomia tropicalis and Dermatophagoides sp mites were the most prevalent in both cities. Conclusions: the results obtained could explain the high prevalence of sensitization to mite allergens and the relevant prevalence of allergic diseases in this region of Colombia.