There were a number of 5 teams that competed with each other under the South Zone of the Ranji Trophy, 1965-66 and the teams included the likes of Hyderabad, Kerala, Andhra, Mysore and Madras. The teams played against each other in the zonal league matches first and they tried their best to become one of the top two teams of the zone. They also competed against each other for securing a birth in the knock out level of the tournament, however, only the teams of Mysore and Hyderabad could do so from the South Zone.

The teams of Hyderabad and Andhra met with each other in the first of the South Zone league matches in the Ranji Trophy, 1965-66 and the match was held at Kothagudium from 26-27 November, 1965. The Hyderabad team got a very good start in the tournament, as it won this match by a margin of an innings and 74 runs to earn the full 9 points from it. The second match of the South Zone saw a clash between the teams of Mysore and Kerala at Bangalore from 27-28 November, 1965. The winner of the match was the Mysore team with a margin of an innings and 148 runs and earned the entire 9 points from the match. The Kerala team appeared in the third match of the zone also and this time, it played against the Madras team at Madras from 04-06 December, 1965. The match was drawn during the stipulated duration and the match officials awarded the Madras and Kerala teams 8 and 3 points, respectively for the match.

The fourth of the South Zone league matches in the Ranji Trophy, 1965-66 was played between the teams of Andhra and Madras and the match took place at Eluru from 10-12 December, 1965. The Madras team played wonderfully in the match and clinched a huge victory of 188 runs to earn 8 points from it. The next match of the South Zone involved the teams of Hyderabad and Mysore and the match was held at Secunderabad from 11-13 December, 1965. The drawn match saw the Mysore team earning 5 points and Hyderabad earning 3 points from it. The teams of Andhra and Mysore then played against each other in the next match at Anantapur from 18-19 December, 1965. The match saw the Mysore team winning by a huge margin of an innings and 140 runs and also earning the entire 9 points from the match.

There was a clash between the teams of Andhra and Kerala in the seventh of the South Zone league matches in the Ranji Trophy, 1965-66 and the match was played at Eluru from 01-03 January, 1966. The Kerala team played well in the match and got a victory of 5 wickets for earning 8 points from the match. The match between the teams of Madras and Hyderabad was also held during the same timing from 01-03 January, 1966 and the match took place at Madras. As the match remained drawn during its specified period of time, the teams of Hyderabad and Madras earned 5 and 3 points, respectively from the match. The teams of Kerala and Hyderabad then clashed with each other in the ninth match of the South Zone. The match that held at Ernakulam from 08-09 January, 1966, saw the Hyderabad team winning by an innings and 91 runs and also earning 9 points from it. The last of the South Zone league matches in the Ranji Trophy, 1965-66 saw a huge clash between the two powerful teams of the Zone, Madras and Mysore and the match was held at Bangalore from 08-10 January, 1966. The Mysore team played wonderfully in the match and eventually won it convincingly by huge margin of 141 runs and also earned 8 valuable points from it.