How to Tie the Surgeon’s Knot by The Blue Quill Angler in Evergreen, CO

The Surgeon’s Knot, like the Blood Knot, is used for connecting two pieces of monofilament. However, the Surgeon’s Knot can be used to attach two pieces of line that differ greatly in diameter making it great for building a tapered leader for fly fishing. When properly tied, the Surgeon’s Knot is typically stronger than the Blood Knot, and it’s especially easy to tie. It won’t take much to master the Surgeon’s Knot, so run through the following steps a few times, then you’ll be ready to hit the water and focus on fishing.

Step One When Tying the Surgeon’s Knot

Surgeons Knot

Bring the main line in from the left with the line to be attached coming in from the right. Overlap the two pieces about six inches as shown in the illustration.

Fly Fishing Surgeon’s Knot Step Two

Pinch the two ends of overlapping line on either side and make a loop with the section in between. Secure the base of the loop between the thumb and index finger of your left hand. Then, take the long and short end of line that’s in your right hand and pass them through the formed loop. Do the same thing a second time for a result that looks like the second illustration.

Completing the Surgeon’s Knot

Gently pull both pieces of line on either side so the loop gets smaller. Lubricate the knot and then pull tight. To further secure the Surgeon’s Knot, you can pull the individual lines coming from the knot. Remember, the strength of the knot is only good if it’s completely tight. This is why we don’t recommend the Surgeon’s Knot for line rated over 30 pounds since that will be harder to fully tighten. While you can trim the tag ends close to the Surgeon’s Knot, this is also a good place to leave a length of line for attaching a fly on a dropper rig.