Recycled polyethylene terephthalate (r-PET) is a widely recycled plastic employed for new textile production in the world. It reduces environmental impact and lowers cost of the production. For the traditional dyeing of polyethylene terephthalate (PET), commercial disperse dyes are generally used. In presented research the recycled r-PET fibres 6 den dyeing with disperse dyes Itosperse: Red, Blue and Yellow (concentration 3 Wt. %) were examined and the influence of the intensifier of a salicylic acid (with concentration of 4 - 10 g/L) in dye bath was investigated. The colour properties of dyed samples and colour fastness to washing were tested. It is concluded that the presence of the intensifier of salicylic acid improves dyeing results, but the optimal concentration differs for each dye. Colour fastness test to washing of the blue dyed samples showed the insignificant changes of colour parameters. In some cases the change of shade in presence of salicylic acid was observed.