1990 Davis Cup
The 1990 Davis Cup was the 79th edition of the Davis Cup, the most important tournament between national teams in men's tennis. 85 teams would enter the competition, 16 in the World Group, 19 in the Americas Zone, 19 in the Asia/Oceania Zone, and 31 in the Europe/Africa Zone. Barbados [Davis Cup team|Barbados], Costa Rica, Guatemala, Togo, Trinidad and Tobago and Zambia made their first appearances in the tournament.
The United [States Davis Cup team|United States] defeated Australia in the final, held at the Florida Suncoast Dome in St. Petersburg, Florida, United States, on 30 November–2 December, to win their 29th title overall.
World Group
Final
'''United States vs. Australia'''World Group qualifying round
Date: 21–23 SeptemberThe eight losing teams in the World Group first round ties and eight winners of the Zonal Group I final round ties competed in the World Group qualifying round for spots in the 1991 World Group.
| Home team | Score | Visiting team | Location | Venue | Door | Surface |
| ' | 4–1 | Brussels | Royal Léopold Club | Outdoor | Clay | |
| ' | 5–0 | Ramat HaSharon | Canada Stadium | Outdoor | Hard | |
| ' | 3–2 | Toronto | National Tennis Centre | Outdoor | Hard | |
| 1–4 | ' | Moscow | Lenin Central Stadium | Indoor | Carpet | |
| ' | 5–0 | Västerås | Rocklundahallen | Indoor | Carpet | |
| 0–5 | ' | London | Queen's Club | Outdoor | Grass | |
| ' | 5–0 | Mexico City | Club Alemán de México | Outdoor | Hard | |
| ' | 3–2 | Split | Športski centar Gripe | Indoor | Clay |
- ,,,, and remain in the World Group in 1991.
- and are promoted to the World Group in 1991.
- ,,,, and remain in Zonal Group I in 1991.
- and are relegated to Zonal Group I in 1991.
Americas Zone
Group I
Group II
- promoted to Group I in 1991.
Asia/Oceania Zone
Group I
- relegated to Group II in 1991.
- and advance to World Group qualifying round.
Group II
- promoted to Group I in 1991.