Pink coloured stable gold sol (lambda(max): 523 nm) has been prepared photochemically in aqueous Triton X-100 (TX-100) medium and used for spectrophotometric determination of cyanide. The colour of the sol decreases on cyanide addition and becomes colourless at the end point. Linear calibration is obtained in the range of 0-26 ppm of cyanide concentration. The relative standard deviation for 8.65 ppm of cyanide is found to be +/-2.03%. The method is simple, rapid and applied for real sample analysis.