Lophomonas is a genus of multi-flagellated protozoans consisting in two species Lophomonas striata and Lophomonas blattarum. Both species are considered endocommensal parasites of some domestic pest insects. While L. striata has no importance in public health, L. blattarum is the causal agent of lophomoniasis, a respiratory tract parasitic infection that mostly affect children and immunocompromised adults. A previous study from our group, reported an important prevalence of L. blattarum in the intestinal tract of American cockroaches (Periplaneta americana), collected in the peridomiciliary zone of houses from an urban area of Panamá. Based on this, we aimed to screen by Methylene Blue-staining the sputum samples from immunocompetent adults (N=80) with bronchopulmonary affections to detect potential carriers of L. blattarum. A total of 53 individuals were included in the analysis. We observed the presence of L. blattarum in 19 out of 53 wet Methylene blue-stained samples. Our results point out a substantial prevalence (35.8%) of L. blattarum positive individuals in an area with high incidence of respiratory problems. In addition, we propose the use of Methylene blue stain as a quick and economic diagnostic tool; this reagent highlights the morphological structures of the parasite making easy its identification.