Aim The effect of heavy metals presence on the decolourization of Reactive Black 5 by Pseudomonas aeruginosa was evaluated. Methods and Results In the current study, a newly isolated strain identified as P. aeruginosa strain Gb 30 was selected for its ability to remove high concentration of Reactive Black 5 and resistance to several heavy metals (Cu2+>Zn2+>Cd2+>Cr6+). Strain Gb30 was used to assess the effect of heavy metals presence on RB5 decolourization. The strain growth exhibited different responses at a fixed concentration of EC50 (10 h) for each heavy metal. The addition of Zn2+ and Cd2+ had no effect on decolourization yield after 24 h of incubation, whereas Cr6+ and Cu2+ ions reduced decolourization up to 17%. In order to understand the relationship between heavy metals contamination and decolourization, experimental data relating the initial decolourization rate of RB5 to the concentrations of single and associated heavy metals were fitted to three different inhibition kinetic models. Conclusions In this study, we showed that P. aeruginosa strain Gb30 could be used for dye removal even at high concentrations of heavy metals. The developed models could provide basic information that may help for the best management of the bacteria-mediated decolourization process at the industrial scale. Significance and Impact of the Study This study opens new directions for the management of textile industry wastewaters containing dyes and heavy metals using bioaugmentation by P. aeruginosa strain Gb30.