Abstract: The effect of different food concentration, substratum, light periodicity, salinity, cyprid density and cyprid age on the settlement of Balanus improvisus were studies. Released larvae were mass reared in 0.6 L glass beakers to the cyprid stage. Then, attachment was monitored once a day. Chaetoceros calcitrans was used as food at three cell concentrations (0.5x105, 1x105 and 2x105 cells mL-1). Larval settlement was carried out on two substratum under three light period (12L:12D, 16L:8D and 8L:16D) at seven salinities (7, 12, 15, 18, 25, 28 and 36 ppt). Cyprid density was used from five to 200 larvae per 5 mL of seawater. Cyprids were aged for one to seven days. The maximum and minimum percent settlement was observed at 2x105 and 0.5x105 cells mL-1, respectively. Cyprids settled in higher numbers on polystyrene compared to glass surface. Percent settlement was higher in 8L:16D than another light periods but, no significant difference in percent settlement between 12L:12D and 16L:8D light periods was seen. Differences in settlement at various salinities were not statistically significant except in 10 ppt which percent settlement was significantly higher. Cyprid density did not have any effect on percent settlement but cyprid age had a significant effect on percent settlement.