diff --git a/backend/run-member-number-migration.js b/backend/run-member-number-migration.js
new file mode 100644
index 0000000..e6073a5
--- /dev/null
+++ b/backend/run-member-number-migration.js
@@ -0,0 +1,96 @@
+const { sequelize } = require('./src/config/database');
+const { QueryTypes } = require('sequelize');
+
+async function runMigration() {
+  try {
+    console.log('🚀 Starting member_number migration...\n');
+    
+    // Step 1: Add column (if not exists)
+    console.log('Step 1: Adding member_number column...');
+    await sequelize.query(`
+      ALTER TABLE group_members 
+      ADD COLUMN IF NOT EXISTS member_number INTEGER
+    `);
+    console.log('✓ Column added\n');
+    
+    // Step 2: Populate for existing members
+    console.log('Step 2: Assigning numbers to existing members...');
+    const [results] = await sequelize.query(`
+      WITH numbered_members AS (
+        SELECT 
+          id,
+          ROW_NUMBER() OVER (
+            PARTITION BY group_id 
+            ORDER BY joined_date ASC, created_at ASC
+          ) as assigned_number
+        FROM group_members
+        WHERE member_number IS NULL
+      )
+      UPDATE group_members gm
+      SET member_number = nm.assigned_number
+      FROM numbered_members nm
+      WHERE gm.id = nm.id
+      RETURNING gm.member_number
+    `);
+    console.log(`✓ Assigned numbers to ${results.length} existing members\n`);
+    
+    // Step 3: Make NOT NULL
+    console.log('Step 3: Setting NOT NULL constraint...');
+    await sequelize.query(`
+      ALTER TABLE group_members 
+      ALTER COLUMN member_number SET NOT NULL
+    `);
+    console.log('✓ NOT NULL constraint set\n');
+    
+    // Step 4: Add unique index
+    console.log('Step 4: Creating unique index...');
+    await sequelize.query(`
+      CREATE UNIQUE INDEX IF NOT EXISTS idx_group_members_member_number 
+      ON group_members(group_id, member_number)
+    `);
+    console.log('✓ Unique index created\n');
+    
+    // Step 5: Verify
+    console.log('Step 5: Verifying migration...');
+    const members = await sequelize.query(
+      `SELECT 
+        gm.member_number,
+        u.full_name,
+        cg.name as group_name
+      FROM group_members gm
+      JOIN users u ON gm.user_id = u.id
+      JOIN chit_groups cg ON gm.group_id = cg.id
+      ORDER BY cg.name, gm.member_number
+      LIMIT 20`,
+      { type: QueryTypes.SELECT }
+    );
+    
+    console.log('\n✅ Migration completed successfully!\n');
+    console.log('Sample members with assigned numbers:');
+    console.log('─'.repeat(70));
+    members.forEach(m => {
+      console.log(`#${m.member_number}\t${m.full_name}\t(${m.group_name})`);
+    });
+    console.log('─'.repeat(70));
+    console.log(`\n✓ Total members checked: ${members.length}`);
+    console.log('\n🎉 Member numbers are now active!');
+    console.log('   Restart your backend server to see them in action.');
+    
+    await sequelize.close();
+    process.exit(0);
+  } catch (error) {
+    console.error('\n❌ Migration failed:', error.message);
+    console.error('\nFull error:', error);
+    await sequelize.close();
+    process.exit(1);
+  }
+}
+
+console.log('═'.repeat(70));
+console.log('  MEMBER NUMBER MIGRATION');
+console.log('  Adding readable serial numbers (1, 2, 3...) to members');
+console.log('═'.repeat(70));
+console.log('');
+
+runMigration();
+