| Singles | |
|---|---|
| 1989 Vitosha New Otani Open | |
| 1988 Champion |  Conchita Martínez |
| Champion |  Isabel Cueto |
| Runner-up |  Katerina Maleeva |
| Score | 6–2, 7–6 |
Conchita Martínez was the defending champion but did not compete that year.
Isabel Cueto won in the final 6–2, 7–6 against Katerina Maleeva.
A champion seed is indicated in bold text while text in italics indicates the round in which that seed was eliminated.
Katerina Maleeva (final) Isabel Cueto (champion)
Laura Golarsa (first round)
Petra Langrová (quarterfinals) Laura Garrone (first round)
Sabrina Goleš (quarterfinals)
Angeliki Kanellopoulou (semifinals) Sabine Hack (second round)Chris Evert was the defending champion but did not compete that year.
Steffi Graf won in the final 6–4, 6–1 against Katerina Maleeva.
Chris Evert was the defending champion and won in the final 7–6, 6–4 against Arantxa Sánchez.
Steffi Graf was the defending champion but did not compete that year.
Steffi Graf was the defending champion but lost in the semifinals to Gabriela Sabatini.
Manuela Maleeva-Fragniere was the defending champion but did not compete that year.
Jana Novotná and Andrea Strnadová were the defending champions but only Novotná competed that year with Laura Golarsa.
Steffi Graf was the defending champion but did not compete that year.
Kathleen Horvath was the defending champion but lost in the first round to Silvia La Fratta.
Chris Evert was the defending champion but lost in the final 3–6, 6–1, 6–4 against Monica Seles.
Steffi Graf was the defending champion and won the final on a walkover against Jana Novotná.
Isabel Cueto won in the final 7–6, 6–2 against Sandra Cecchini.
Isabel Cueto was the defending champion but lost in the quarterfinals to Maria Strandlund.
Gabriela Sabatini was the defending champion and won in the final 6–0, 6–2 against Isabel Cueto.
Steffi Graf was the defending champion and won in the final 6–4, 6–2 against Katerina Maleeva.
Claudia Kohde-Kilsch and Jana Novotná were the defending champions but only Novotná competed that year with Tine Scheuer-Larsen.
Katerina Maleeva was the defending champion but did not compete that year.
Manuela Maleeva was the defending champion but lost in the second round to Catarina Lindqvist.
Steffi Graf was the defending champion but did not compete that year.
Martina Navratilova defeated Jennifer Capriati in the final, 6–2, 6–4 to win the singles tennis title at the 1990 Family Circle Cup.
