The 2019 Thindown Challenger Biella was a professional tennis tournament played on outdoor red clay courts. It was part of the 2019 ATP Challenger Tour. It took place in Biella, Italy between 16 and 22 September 2019.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 Spain | Alejandro Davidovich Fokina | 109 | 1 | |
| Spain | Jaume Munar | 112 | 2 | |
 Slovakia | Andrej Martin | 114 | 3 | |
 Italy | Paolo Lorenzi | 121 | 4 | |
 Japan | Taro Daniel | 137 | 5 | |
| Italy | Lorenzo Giustino | 138 | 6 | |
| Italy | Alessandro Giannessi | 140 | 7 | |
| Italy | Gianluca Mager | 142 | 8 | |
| Italy | Filippo Baldi | 148 | 9 | |
| Italy | Federico Gaio | 154 | 10 | |
| Spain | Mario Vilella Martínez | 190 | 11 | |
 Argentina | Marco Trungelliti | 196 | 12 | |
| Spain | Tommy Robredo | 201 | 13 | |
| Italy | Stefano Napolitano | 203 | 14 | |
 France | Elliot Benchetrit | 211 | 15 | |
| Argentina | Carlos Berlocq | 228 | 16 |
The following players received wildcards into the singles main draw:
Federico Arnaboldi Matteo Arnaldi Giacomo Dambrosi Gabriele Felline Pietro RondoniThe following player received entry into the singles main draw using a protected ranking:
The following players received entry from the qualifying draw:
Oscar José Gutierrez Fernando RomboliSee main article: 2019 Thindown Challenger Biella – Singles.
Gianluca Mager def. Paolo Lorenzi 6–0, 6–7(4–7), 7–5.See main article: 2019 Thindown Challenger Biella – Doubles.
Tomislav Brkić / Ante Pavić def. Ariel Behar / 
Andrey Golubev 7–6(7–2), 6–4.