This bachelor thesis is about the resistance mechanisms and virulence factors of nontuberculous mycobacteria, with a focus on biofilms. Biofilms are microorganism structures, which are more resistant to outside influences, especially to antibiotics and disinfectants. They can cause various infections and disseminated disease. The formation of the biofilm formation with its different stages is described. Moreover, the biofilm structure and its most essential components is reviewed: each biofilm consists of different amounts of lipids, nucleic acids, mycolic acids, and polysaccharides. Additionally, genes, involved in biofilm formation such as guaB2 and gtf, which regulate the synthesis of essential matrix compounds, are discussed. Standard antibiotic substances as well as new generation substances with antibiofilm effect are discussed; first, inhibitory mechanisms and target points of common antibiotics, like ciprofloxacin, clarithromycin, amikacin, clofazimine, cefoxitin and streptomycin. Then, new therapy strategies against nontuberculous mycobacteria biofilms, such as AM-228, iron deprivation, the use of metal nanoparticles and enzymes, which attack the DNA machinery of mycobacteria, are reviewed. In addition to antibiotics, new strategies are also able to prevent or inhibit biofilm formation. However, more studies are required to fully understand the mechanisms of biofilm formation and to identify the most efficacious antibiofilm agents.