Jung, who will be fighting for the first time since 2013, came in at 145.5, as did Bermudez.
The only fighter who missed weight was Bec Rawlings, who weighed 117.5 for her strawweight bout with Tecia Torres.
UFC FN 104 will take place in Houston, Texas.
FS1 Main Card – 10 pm ET/7 pm PT
Dennis Bermudez (145.5 lbs) vs Chan Sung Jung (145.5 lbs)
Alexa Grasso (116) vs Felice Herrig (115.5)
Abel Trujillo (156) vs James Vick (155.5)
Ovince Saint Preux (205) vs Volkan Oezdemir (206)
Anthony Hamilton (258.5) vs Marcel Fortuna (210.5)
Jessica Andrade (115.5) vs Angela Hill (116)
FS1 Prelims – 8 pm ET/5 pm PT
Adam Milstead (233.5) vs Curtis Blaydes (264.5)
Chas Skelly (146) vs Chris Gruetzemacher (145)
Ricardo Ramos (135) vs Michinori Tanaka (135)
Tecia Torres (115.5) vs Bec Rawlings (117.5)*
UFC FIGHT PASS Prelims – 7 pm ET/4 pm PT
Alex Morono (170) vs Niko Price (170.5)
Daniel Jolly (204.5) vs Khalil Rountree Jr. (205)
*Rawlings missed weight and will forfeit 20 percent of her purse to her opponent Tecia Torres