Blood Knot Tying: Step by Step Instructions and Diagram

Blood Knot

Blood Knot

What Is It?

The blood knot, also known as the double blood knot, joins two fishing lines of similar sizes like different sections of the leader or tippet. It has a breaking strength of around 83%. Its name originated from its use on the business end of a Cat o’ nine tails whip.

How to Tie a Blood Knot

How to Tie a Blood Knot


  1. Note that the tag ends are at right angles to the line.
  2. If you find it hard controlling the tippet ends go for the easier, faster speed blood knot. Though not a true blood knot, it has approximately the same strength.
  3. It can join a leadcore to the leader.


  1. Improved blood knot – Fares well in connecting a thicker line to a thinner one. For example a heavy shock material to a lighter class tippet.
  2. Half blood knot – For attaching a fishing hook to the line. It can also join a line to a snap, swivel or lure.




  • Strong
  • Compact
  • Versatile
  • Smooth shape
  • Breaks less often
  • Works with lines of varying diameters
  • It can connect braid to braid, braid to mono, mono to mono and braid to fluorocarbon
  • If not trimmed closely can catch on to rod guides


  1. In fly fishing.
  2. To construct fishing leaders.
  3. As a decorative stopper knot in sailing
  4. For leader to tippet and line to leader connections.

Tying a Blood Knot: Video


  1. Double surgeon’s knot – Slips less though weaker.
  2. J knot – Slightly more powerful albeit difficult to tie.
  3. Double uni– Stronger for braided lines.
  4. Uni knot – Sturdier and less unwieldy.
  5. Uni to uni – Retains around 90% of the line strength making it more robust.
  6. Albright knot – Joins lines of different diameters.
  7. Double fisherman’s knot – Employs fewer twists in the 2
  8. Nail knot– Unites varying diameter lines. Also used in carp fishing versus the blood knot’s use in fly fishing only.

Similar Knots

  1. Blood loop knot – Connects a hook snood to a trace body

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