Polylactide (PLA) fibers were dyed with Disperse Blue 79 in supercritical carbon dioxide (SC-CO2)The effects of dyeing conditions such as the temperature, pressure, and time on the dyeing and mechanical properties were discussed in comparison with those in water. A major advantage of dyeing PLA in SC-CO2 over dyeing PLA in an aqueous medium was its much better retention of the fiber strength. The loss of the breaking strength of PLA dyed in SC-CO2 at 120 degrees C for 60 min was 9.22% versus a 44.66% loss in aqueous dyeing at the same temperature. (c) 2007 Wiley Periodicals, Inc.