A series of electrolyte-free reactive dyes containing two quaternary ammonium salt groups as soluble moieties and one epoxy structure as the reactive group have been synthesised. The structures of the synthesised dyes were confirmed by Fourier Transform-infrared, proton nuclear magnetic resonance and elemental analysis, and their dyeing properties on cotton were studied using an electrolyte-free dyeing process. The results indicate that electrolyte-free reactive dyes with these structures give a high exhaustion rate, a high fixation rate and good build-up properties on cotton. Fastness properties were, in general, also very good. The optimal dyeing process of these electrolyte-free dyes for cotton fibre was 60°C with 20 g ⁄ l sodium carbonate.