Strength (Str): Strength measures physical power. A high Strength adds modifiers to melee damage and chance to hit, which is important for characters that use close-combat weapons (vibroblades, lightsabers).
Dexterity (Dex): Dexterity measures agility and reflexes. A high Dexterity adds modifiers to ranged attack rolls (blasters) and increases a character's Defense, making them harder to hit.
Constitution (Con): Constitution epresents health and resiliency. A high Constitution adds modifiers to the vitality points gained at each level up. Constitution also determines what types of implants the character can equip. This attribute is important to all classes.
Wisdom (Wis): Wisdom represents willpower and perception. A high Wisdom adds modifiers to Jedi Force Points and Force Power saving throws. The Force Powers of a Jedi with high Wisdom are also much harder to resist.
Intelligence (Int): Intelligence represents knowledge and reasoning. A high Intelligence adds modifiers to the number of points a character has to spend on essential skills.
Charisma (Cha): A high Charisma increases the potency of a character's Force Powers. It also reduces the penalty when using Force Powers of an opposing alignment (a light side character with a high Charisma can use dark side powers with less of a penalty), and a high Charisma also improves your companions' chance to hit. Finally, Charisma influences a character's Persuade skill.