private void Form1_Load(object sender, EventArgs e)
{
  this.tabControl1.DrawMode = System.Windows.Forms.TabDrawMode.OwnerDrawFixed;
  this.tabControl1.DrawItem += new DrawItemEventHandler(this.tabControl1_DrawItem);
}
private void tabControl1_DrawItem(object sender, System.Windows.Forms.DrawItemEventArgs e)
{
  StringFormat sf = new StringFormat();
  sf.LineAlignment = StringAlignment.Center;
  sf.Alignment = StringAlignment.Center;
  if (e.Index == tabControl1.SelectedIndex)
    e.Graphics.FillRectangle(Brushes.Red, e.Bounds.X, e.Bounds.Y, e.Bounds.Width, e.Bounds.Height);
  else
    e.Graphics.FillRectangle(Brushes.White, e.Bounds.X, e.Bounds.Y, e.Bounds.Width, e.Bounds.Height);
  e.Graphics.DrawString(((TabControl)sender).TabPages[e.Index].Text,
  System.Windows.Forms.SystemInformation.MenuFont, new SolidBrush(Color.Black), e.Bounds, sf);
}

this.tabControl1.DrawMode = System.Windows.Forms.TabDrawMode.OwnerDrawFixed;
this.tabControl1.DrawItem += new DrawItemEventHandler(this.tabControl1_DrawItem);

private void tabControl1_DrawItem(object sender, System.Windows.Forms.DrawItemEventArgs e)
{
   Font fntTab;
   Brush bshBack;
   Brush bshFore;
   if ( e.Index == this.tabControl1.SelectedIndex)
   {
     fntTab = new Font(e.Font, FontStyle.Bold);
     bshBack = new System.Drawing.Drawing2D.LinearGradientBrush(e.Bounds, SystemColors.Control, SystemColors.Control, System.Drawing.Drawing2D.LinearGradientMode.BackwardDiagonal);
     bshFore = Brushes.Black;
   }
   else
   {
     fntTab = e.Font;
     bshBack = new SolidBrush(Color.Blue );
     bshFore = new SolidBrush(Color.Black);
   }
   string tabName  = this.tabControl1.TabPages[e.Index].Text;
   StringFormat sftTab = new StringFormat();
   e.Graphics.FillRectangle(bshBack, e.Bounds);
   Rectangle  recTab = e.Bounds;
   recTab = new Rectangle( recTab.X,  recTab.Y + 4,  recTab.Width,  recTab.Height - 4);
   e.Graphics.DrawString(tabName, fntTab, bshFore, recTab, sftTab);
}