The dyeing of textile fibres of poly-ethylene terephthalate (PET) in a supercritical medium is an environmentally friendly technological alternative to the conventional water-based dyeing process. In this work, the solubility of the monoazo disperse dye 4-((2,6-dichloro-4-nitrophenyl) azo)-N-(cyanoethyl)-N-(acetoxyethyl) aniline (CAS number 5621-31-4, also known as "C.I. Disperse Orange 30") in supercritical carbon dioxide (SC-CO2) was experimentally studied within a dye mole fraction range from 6.55 . 10 (6) to 9.31 . 10 (6) and over the temperature range from (303.15 to 333.15) K. The resulting measured solid-fluid transition pressures fell in the range from (9.93 to 14.82) MPa. The measurements were performed using the static-synthetic method. The dye solubility in carbon dioxide was found to increase with increasing pressure. The experimental results were correlated with a model that combines the Peng-Robinson equation of state for describing the fluid phase and a standard equation for the fugacity of the pure dye in solid state. The reference state for such equation is the sublimation curve of the pure dye. (C) 2012 Elsevier Ltd. All rights reserved.