Blood Knot
Blood Knot
The classic knot for joining two lines of similar diameter. The Blood Knot creates a slim, balanced barrel that runs smoothly through rod guides — essential for building leaders and fly fishing tippets.
Video by Sport Fishing Report on YouTube
About the Blood Knot
The Blood Knot has been a staple of fly fishing and light tackle angling for over a century. Its symmetrical design distributes stress equally across both lines, and its slim profile means it passes through rod guides without snagging.
It works best joining lines within one or two pound-test of each other. For very different diameters, the Surgeon's Knot is a better choice. With practice an experienced angler can tie a Blood Knot in under a minute.
Best Used For
Ideal applications
- ✓ Joining two similar-diameter lines
- ✓ Building tapered leaders
- ✓ Adding tippet to leader
- ✓ Fly fishing connections
- ✓ Light tackle leader systems
Not ideal for
- ✗ Lines of very different diameters — use Surgeon's instead
- ✗ Braided line connections
- ✗ Heavy mono over 30 lb
Step-by-Step Instructions
Follow these 5 steps to tie the Blood Knot. Watch the video above while following along.
Step 1: Overlap the two lines
Lay the two lines parallel with about 10 inches of overlap, pointing in opposite directions. Hold the center crossing point between thumb and forefinger.
Step 2: Wrap the first line
Take the tag end of line A and wrap it around line B five times working away from center. Bring the tag end back and hold at center.
Step 3: Wrap the second line
Repeat with line B — wrap around line A five times, bring back to center. This tag end must point the opposite direction from the first.
Step 4: Thread tag ends through center
Push both tag ends through the center opening from opposite sides. This locks the two sets of wraps together into the barrel.
Step 5: Wet and pull tight
Wet thoroughly. Slowly pull both standing lines in opposite directions. The barrel will compress evenly. Trim both tag ends close.
Pro Tips
- 5 wraps on each side for most applications
- Tag ends must pass through center in opposite directions
- Tighten very slowly and evenly
- Hold both tag ends while tightening to stay aligned
Common Mistakes
- Unequal number of wraps on each side
- Tag ends through center in same direction — must be opposite
- Not wetting before tightening
- Rushing the final tightening step