Gustavo Kuerten won the singles tennis title at the 1999 Monte Carlo Open when Marcelo Ríos retired from the final with the scoreline at 6–4, 2–1. Carlos Moyá was the defending champion, but lost in the quarterfinals to Jérôme Golmard.

Seeds

The top eight seeds received a bye to the second round. • # 🇪🇸 Carlos Moyá (quarterfinals) • # 🇷🇺 Yevgeny Kafelnikov (second round) • # 🇬🇧 Tim Henman (second round) • # 🇺🇸 Todd Martin (withdrew) • # 🇦🇺 Mark Philippoussis (quarterfinals) • # 🇸🇰 Karol Kučera (second round) • # 🇺🇸 Andre Agassi (withdrew) • # 🇬🇧 Greg Rusedski (second round) • # Marcelo Ríos (final, retired) • # 🇪🇸 Álbert Costa (quarterfinals) • # Goran Ivanišević (first round) • # 🇸🇪 Thomas Enqvist (second round) • # 🇧🇷 Gustavo Kuerten (champion) • # 🇩🇪 Tommy Haas (second round) • # 🇪🇸 Félix Mantilla (semifinals) • # 🇸🇪 Thomas Johansson (first round)

Draw

Finals

Top half

Section 1

Section 2

Bottom half

Section 3

Section 4