Non-tuberculous Mycobacteria (NTM) include those Mycobacterium species that are not members of the Mycobacterium tuberculosis complex. These species are distributed ubiquitously in soil and water and can be commonly found in potable water. Recent reports show positivities of about 42,3% of waters contaminated with NTM in Germany. In recent years, NTM have emerged as a major cause of opportunistic infections in those who have AIDS or are immunocompromised due to transplantation or chemotherapy. There are also some reports of immunocompetent patients infected with NTM, directly related with contaminated water systems. Therefore, the development of methods to rapidly and accurately detect NTM is of the utmost importance in order to prevent outbreaks of NTM contamination. The Bactec system, usually used for the detection of Mycobacterium tuberculosis in clinical samples can be a useful tool for the detection of NTM in water. The objective of this work was to evaluate this system for this propose. A loopfull of pure cultures of Mycobacterium smegmatis, Pseudomonas aeruginosa, and Staphylococcus aureus were diluted in 1L of distilled sterile water and filtered through a 0,22 um membrane (Millipore, USA). The membrane was then ressuspended in 5 mL of the original water sample. Decontamination was performed by the NALC-NaOH method (BBL Mycoprep - Becton Dickinson, USA), Petroff's method, and Oxalic Acid method. Alternatively, the membrane was ressuspended and incubated at 37C in peptone (Oxoid, UK), supplemented with different classes of antibiotics (cephalosporins, beta-lactams and aminoglycosides). After decontamination and incubation, the samples were introduced in the Bactec medium bottles (Becton Bickinson, USA). The positive results in the Bactec system are detected by a sensitive fluorometric sensor that detects oxygen consumption as the mycobacterial organisms grow. Positive results obtained by the Bactec system were confirmed by usual biochemical and staining methods. Includes 4 references, figures.