Unfertilised rainbow trout (Oncorhynchus mykiss) eggs were stored in vitro in coelomic fluid (CF) and in trout artificial medium (TAM) for 3 and 9 days at 12°C. Eggs held in vivo in the body cavity for 3 and 9 days were obtained from the same females and used as a control. Eggs were fertilised with a pool of sperm obtained from 5 males. The percentage of embryos reaching eyed stage, hatching and yolk-sac resorption, as well as morphological abnormalities were recorded as an index of egg quality (fertility and developmental success). Unfertilised eggs stored 3 days in vitro in CF exhibited the same quality as eggs stored 3 days in vivo (control). After a 9-day storage in CF, egg quality was lower for the 2 females analysed. For eggs held 3 days in TAM, eying, hatching and swim-up rates were significantly lower than in vivo. After 9 days in TAM, fertility and developmental success were extremely low. Unfertilised eggs stored 3 days in vitro in CF and in vivo (control) exhibited the same percentage of morphological abnormalities at yolk-sac resorption. Surprisingly, no malformation was observed at yolk-sac resorption when unfertilised eggs were stored 3 days in vitro in TAM. This study demonstrates that coelomic fluid can be used at 12°C for external storage of trout eggs for at least 3 days without loss of egg quality. In contrast, a 3-day storage at 12°C in trout artificial medium induces a significant loss of egg quality.