The effect of depth on oysters in suspension culture from a petroleum platform off the Texas coast was monitored for 20 months. Growth and condition was similar for adult oysters culture at five levels down to 8 m. Oysters had a growth rate of 1.2 mm (level 3) to 1.4 mm (level 1) per month, representing an increase in length of 94% to 150% for the 20 months. The condition was best in June 1973 after five months placement offshore (condition index of 14.8, 15.5, 14.7, 13.5 and 13.2 for levels 1 through 5, respectively). The condition was lowest in June 1974 (2.2, 2.1, 1.3, 1.4 and 1.5 for levels 1 through 5, respectively). Ninety oysters died during the experimental period. Sixty-three percent were from the upper two levels. One hundred forty-five oysters disappeared. Fifty-eight percent were from the bottom two levels. Most oysters disappeared in February 1974 (47% of all disappearances).