| Mode: | Basketball |
| Year: | 1989–90 |
| Prev Year: | 1988–89 |
| Next Year: | 1990–91 |
| Team: | Colorado State Rams |
| Conference: | Western Athletic Conference |
| Short Conf: | WAC |
| Record: | 21–9 |
| Conf Record: | 11–5 |
| Hc Year: | 3rd |
| Champion: | WAC Regular season co-champions Mile High Classic champions |
The 1989–90 Colorado State Rams men's basketball team represented Colorado State University as a member of the Western Athletic Conference during the 1989–90 college basketball season. The team was led by head coach Boyd Grant. The Rams finished 21–9 and won the WAC regular season title with a 11–5 conference record. The team received an at-large bid to the NCAA tournament as the No. 10 seed in the West region. The Rams were beaten by No. 7 seed Alabama in the first round.
|-!colspan=9 style=| Regular season
|-!colspan=9 style=| WAC tournament|-!colspan=9 style=| NCAA tournament[2]
See main article: 1989–90 NCAA Division I men's basketball rankings.