The 2019 Milex Open was a professional tennis tournament played on green clay courts. It was the fifth edition of the tournament which was part of the 2019 ATP Challenger Tour. It took place in Santo Domingo, Dominican Republic between 7 and 13 October 2019.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 Argentina | Federico Delbonis | 74 | 1 | |
 Bolivia, Plurination;al State of | Hugo Dellien | 85 | 2 | |
| Argentina | Leonardo Mayer | 97 | 3 | |
 Brazil | Thiago Monteiro | 105 | 4 | |
| Argentina | Guido Andreozzi | 111 | 5 | |
 India | Sumit Nagal | 135 | 6 | |
| Argentina | Facundo Bagnis | 150 | 7 | |
| Argentina | Federico Coria | 154 | 8 | |
 Italy | Federico Gaio | 155 | 9 | |
 Spain | Pedro Martínez | 157 | 10 | |
| Italy | Alessandro Giannessi | 166 | 11 | |
| Spain | Mario Vilella Martínez | 182 | 12 | |
| Argentina | Facundo Mena | 198 | 13 | |
 Serbia | Peđa Krstin | 200 | 14 | |
| Argentina | Andrea Collarini | 204 | 15 | |
 Colombia | Daniel Elahi Galán | 206 | 16 |
The following players received wildcards into the singles main draw:
The following player received entry into the singles main draw as an alternate:
See main article: 2019 Milex Open – Singles.
Juan Pablo Varillas def. Federico Coria 6–3, 2–6, 6–2.See main article: 2019 Milex Open – Doubles.
Gonzalo Escobar def. Orlando Luz / 
Luis David Martínez 6–7(5–7), 6–4, [12–10].