Oyster recruitment was monitored in Karantina Island near Izmir, Turkey, from May to October 1999. The aim of the study was to determine the recruitment pattern for six months and the most suitable time to collect oyster spat from nature. Oyster and mussel shells were used as substrates in spat collectors. Five groups of each type of collector were deployed from May to August. The recruitment levels were highest in the groups deployed on June 16, with 4069 and 1575 oyster spats collected on the oyster and mussel shell collectors, respectively. Spat recruitment varied considerably between collector types as well as between the outsides and insides of shells (p < 0.05). Spats larger than 10 mm were found on the second or third sampling date in each group for both oyster and mussel shell collectors. Barnacles (Balanus sp.) settled on both collector types in high numbers throughout the study. Data suggest that maximum recruitment in this area is most likely to occur on both collector types between May and mid-June.