In presented research the recycled polyethylene terephthalate fibres were dyed with disperse dyes Itosperse Blue (concentration 2 Wt. %) and the influence of the intensifier of a salicylic acid (with concentration of 4 g/L, 6 g/L, 8 g/L and 10 g/L) in dye bath was investigated. The colour properties of dyed samples were tested.