Objective. To compare degrading capacity of organic matter of three isolated strains of Pseudomonas genre, of Las Quintas Swamp, through Oxygen Biochemical Demand technique Method. The biological material was collected from water of Las Quintas Swamp, which included three samples composed of fifteen sub-samples, selected on convenience basis. The identification technique was BBLTM CrystalTM Identification System – BD, and degradation verification was by DBO5. Results. Bacteria found in studied water were: Burkhodelia cepacia (C1), Pseudomonas alkcaligens (C2) y Pseudomonas aeruginosa (C3). In each zone (Z), bacteria behave slightly different; however, all of them showed effectiveness for organic matter degradation: In Z1, C1 showed a degrading capacity of 86.22%; C2 86.35%; and C3 86.83%. In Z2, C1 98.93%; C2 85.87%; and C3 86.98%. In Z3, C1 87.47%; C2 79.98%; and C3 87.86%. Conclusions. Results of this study led to learn about degradation capacity of organic matter by native strains. Isolated bacteria showed an acceptable increase of biomass, Z3 being the one which presented higher microbial proliferation with a 43%, seconded by Z2 and Z1, with microbial proliferation percentages of 37% and 20% respectively. Results suggested that isolated bacteria increase the efficiency of organic matter degradation, which saturates the ecosystem under study, and may be used on biotechnological processes.