Banana propagation (Musa sp.) can be done in different ways: by seed and vegetatively by cuttings or in vitro. In traditional method, vegetatively by cuttings, even with material of excellent quality, the process is slow and allows the spread of diseases and pests. Tissue culture, genetic manipulation and molecular biology are being used for plant breeding thus allowing the development of new varieties. Among the different kind of tissue culture one of the most used is micropropagation that is currently responsible for producing seedlings of various species for commercial purposes. The success of micropropagation depends on the sequence of phases or stages, where the success of each one is necessary for the success of the next one and of the explant introduction in the culture medium (establishment), whose success depends on efficient sterilization of explants to be established. In the establishment phase of cultivation, contamination can compromise micropropagation. When it is exogenous the possibility of control of fungi and bacteria is substantial but when the contamination is endogenous, the consequences may be limiting, and there may be loss of time, financial resources and genetic material. This study aimed to evaluate the efficiency of decontamination of banana explants in vitro during the establishment, with the use of antibiotic ampicillin sodium and chloramphenicol added to the culture medium. Antibiotics were added separately to the culture medium at concentrations of 0, 5, 10, 15 and 20 mg L^-1. Data were subjected to variance analysis and means compared by Tukey test at 5% probability. The results showed that the concentration of 15mg L^-1 of the antibiotics decreased by 20% bacterial and fungal contamination and also shown lower oxidation of the explants.