There were 5 teams which competed against each other under the East Zone of the Ranji Trophy, 1989-90, one of the leading domestic cricket tournaments in India. All the regular teams were mainly representing various states from the Eastern region of India and the teams included the likes of Assam, Orissa, Tripura, Bengal and Bihar. They played the matches with great enthusiasm and cricketing excellence. All the teams tried their best to claim the top spot in the zone and to get a chance for competing with the top teams of the other zones in the knock out level of the tournament. However, the teams from Bengal and Bihar eventually became successful after earning a total of 61 and 60 points respectively from the zonal level league matches.

The first of the East Zone league matches in the Ranji Trophy, 1989-90 was played between the teams of Assam and Tripura at Guwahati from 13-16 November, 1989. The match remained drawn during the stipulated duration and the match officials awarded the Assam and Tripura teams 14 and 4 points respectively. The Bihar and Assam teams played against each other in the second match of the zone and the match was held at Ranchi from 20-22 November, 1989. The Bihar team played wonderfully in the match and it earned 22 points from it by clinching a very good victory of an innings and 5 runs. The Assam team also earned 2 points from the match. The third match of the zone involved the teams like Bengal and Tripura and the match took place at Calcutta from 20-22 November, 1989. The drawn match saw the Bengal team earning 13 points and Tripura earning 5 points from it.

The Tripura team appeared in the fourth of the East Zone league matches in the Ranji Trophy, 1989-90 also and this time it played against the Orissa team at Cuttack from 25-27 November, 1989. The Orissa team earned 22 points from the match by winning it with a very good margin of an innings and 103 runs and the Tripura team also earned 3 points from the match. The next match of the zone saw the teams of Bengal and Assam playing against each other at Kolkata from 25-27 November, 1989. The winner of the match was the Bengal team with a wonderful margin of an innings and 120 runs and the team also earned 24 points from the match. The Assam team earned 4 points from the match, as well. The teams of Bihar and Bengal played against each other in the next match of the zone, which was held at Patna from 30 November-02 December, 1989. The Bengal and Bihar teams earned 12 and 6 points, respectively from the drawn match.

The match between the teams of Orissa and Bihar was the seventh of the East Zone league matches in the Ranji Trophy, 1989-90 and the match was organised at Cuttack from 05-07 December, 1989. The match could not yield any specific result and as a result, the Bihar and Orissa teams earned 10 and 8 points respectively from the drawn match. The Orissa team then played against the Bengal team in the next match of the East Zone and the match took place at Baripada from 12-14 December, 1989. The Orissa and Bengal teams earned 14 and 12 points, respectively from the match, as it remained drawn during the specified period of time. The Orissa team appeared in the next match of the zone also and this time it played against the Assam team at Cuttack from 17-19 December, 1989. The match officials awarded the Orissa and Assam teams 15 and 8 points respectively for the drawn match. The last of the East Zone league matches in the Ranji Trophy, 1989-90 saw the Tripura and Bihar teams playing against each other at Agartala from 13-15 January, 1990. The Bihar team played extremely well in the match and clinched a victory of an innings and 92 runs for earning 22 points from the match. The match also saw the Tripura team earning 4 points from it.