| Doubles | |
|---|---|
| 1998 Croatia Open Umag | |
| Champions |  Neil Broad  Piet Norval [1] |
| Runners-up |  Jiří Novák David Rikl |
| Final score | 6–1, 3–6, 6–3 |
The 1998 Croatia Open Umag was a tennis tournament played on outdoor clay courts in Umag, Croatia that was part of the International Series of the 1998 ATP Tour. The tournament was held from July 27 through August 2, 1998.
Champion seeds are indicated in bold text while text in italics indicates the round in which those seeds were eliminated.
Neil Broad / Piet Norval (champions) Jiří Novák / David Rikl (final)
Sander Groen / 
Gábor Köves (first round)
Massimo Ardinghi / Vincenzo Santopadre (quarterfinals)| First round | Quarterfinals | Semifinals | Final [1] | ||||||||||||||||||||||||
| 1 | N Broad P Norval | 6 | 7 | ||||||||||||||||||||||||
T Krupa  B Urh | 3 | 6 | 1 | N Broad P Norval | 5 | 7 | 6 | ||||||||||||||||||||
 I Karlović I Ljubičić | 6 | 7 | I Karlović I Ljubičić | 7 | 5 | 3 | |||||||||||||||||||||
 Ó Ortiz  M Puerta | 2 | 6 | 1 | N Broad P Norval | 6 | 6 | |||||||||||||||||||||
C Brandi  K Carlsson | 7 | 6 | C Brandi K Carlsson | 3 | 4 | ||||||||||||||||||||||
| 3 | S Groen G Köves | 5 | 4 | C Brandi K Carlsson | 6 | 3 | 6 | ||||||||||||||||||||
 C Martinez-Comet M Roy-Girardi | 5 | 7 | 7 | C Martinez-Comet M Roy-Girardi | 4 | 6 | 2 | ||||||||||||||||||||
| E Nicolás G Puentes | 7 | 6 | 6 | 1 | N Broad P Norval | 6 | 3 | 6 | |||||||||||||||||||
| L Bale C Haggard | 4 | 6 | 6 | 2 | J Novák D Rikl | 1 | 6 | 3 | |||||||||||||||||||
| L Friedl P Kovačka | 6 | 3 | 2 | L Bale C Haggard | 7 | 7 | |||||||||||||||||||||
| 4 | M Ardinghi V Santopadre | 6 | 6 | 4 | M Ardinghi V Santopadre | 6 | 5 | ||||||||||||||||||||
| R Carretero C Moyá | 0 | 3 | L Bale C Haggard | 0 | 3 | ||||||||||||||||||||||
 D Pescariu D Sanguinetti | 6 | 2 | J Novák D Rikl | 6 | 6 | ||||||||||||||||||||||
| JI Carrasco J Velasco Jr. | 5 | R | D Pescariu D Sanguinetti | 4 | 4 | ||||||||||||||||||||||
| 2 | J Novák D Rikl | 5 | 6 | 6 | 2 | J Novák D Rikl | 6 | 6 | |||||||||||||||||||
| D Islambegovic E Rasberger | 7 | 3 | 2 | ||||||||||||||||||||||||
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