Knot guide · Beginner

Surgeon's Knot: How to Tie It

The surgeon's knot is a double or triple overhand tied with both lines together, and it is the fastest reliable way to join two lines of similar diameter. It is the join you can manage with numb hands in failing light, which is exactly when you tend to need one.

Joining similar diameter linesTippet to fly leaderPaternoster linksQuick bank side repairs

Published by the GilledIt editorial team · Last reviewed 2026-07-07 · Part of the fishing knot library

Step by step

How to tie the surgeon's knot

  1. 1

    Overlap the lines

    Lay the two lines alongside each other, overlapping by about 15cm and pointing in opposite directions.

  2. 2

    Tie an overhand together

    Treating both lines as one, tie a simple overhand knot, pulling the whole leader or hooklength through the loop.

  3. 3

    Pass through again

    Pass everything through the loop a second time, and a third time for the triple surgeon's.

  4. 4

    Seat evenly

    Wet the knot, then pull all four ends evenly so the knot seats in one neat bundle. Pulling evenly is the difference between full strength and a knot that fails on the strike.

  5. 5

    Trim both tags

    Trim both tag ends close to the finished knot.

Two rules apply to every knot: wet it with saliva before pulling it tight, because dry friction weakens mono and fluorocarbon at the exact point you need strength, and tighten slowly, then test with a firm pull before you cast.

How strong is it?

Retains around 90% of line strength, more in its triple form. Exact figures vary with line type, diameter and how well the knot is tied, so treat any percentage as a guide, not a guarantee.

When to use the surgeon's knot

Joining two lines of similar diameter quickly, attaching tippet to a fly leader, or building a paternoster link, especially mid session when speed matters. It is bulkier than a blood knot and sits slightly off axis, so it is not the join for repeated casting through small rings.

Surgeon's Knot: common questions

Joining two lines of similar diameter quickly: repairing a mainline, attaching tippet to a fly leader, or building a paternoster link. Because it is just a double or triple overhand tied with both lines together, it is the join you can still manage with cold hands in failing light.

The double is the standard and retains around 90% of line strength; passing everything through a third time makes the triple, which tests a little stronger and is popular with fly anglers on fine tippets. The triple is slightly bulkier, so pick based on how much strength matters versus neatness.

Almost certainly uneven seating. All four ends must be pulled evenly so the knot beds down in one neat bundle; pull only two and part of the knot stays loose and slips under sudden load. Wet it, seat it evenly, and test it with a firm pull before fishing.

Surgeon's for speed and reliability mid session, blood knot for neatness. The blood knot sits slimmer and straighter, which suits joins that pass repeatedly through small rod rings, but it is slower and fiddlier to tie, especially in poor light or cold weather.

Keep learning

Related knots

Albright Knot

Joining lines of clearly different diameters: braid to a thick mono or fluorocarbon shock leader for distance casting, or backing to a fly line. For lines of similar diameter, a double grinner or surgeon's knot is the simpler choice.

Read the guide

Grinner Knot (Uni Knot)

Hooks, swivels and leads on any line type, especially when you need a dependable knot tied by feel in the dark or in heavy mono. Tie two grinners facing each other on overlapping lines and you have the double grinner, a sensible alternative to the FG knot for joining braid to a leader.

Read the guide

Figure-of-Eight Loop

Any time you need a loop: hooklength connections, feeder attachments and method rigs. Loop to loop is the quickest way to change hooklengths on the bank; just make sure the loops seat in a square handshake, not a strangling girth hitch, which costs you strength.

Read the guide

For all ten knots in one long read, see the fishing knots guide, or browse the full knot library. Ready to put it to work? The carp rig library shows what to tie next.

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