The 1999 International Raiffeisen Grand Prix was a men's tennis tournament played on Clay in St. Pölten, Austria that was part of the World Series of the 1999 ATP Tour. It was the nineteenth edition of the tournament and was held from 17 May until 23 May 1999. Second-seeded Marcelo Ríos won the singles title.
See main article: 1999 International Raiffeisen Grand Prix – Singles. Marcelo Ríos defeated 
Mariano Zabaleta, 4–4, retired.
See main article: 1999 International Raiffeisen Grand Prix – Doubles. 
Andrew Florent / 
Andrei Olhovskiy defeated Brent Haygarth / Robbie Koenig, 5–7, 6–4, 7–5.