1998 saw the 14th ion of the Yamaha Thailand Cup.
It was Thailand's main inter-provincial competition, played between qualifiers from various regions.
The first round saw four groups of four teams, of which the top two sides qualified for the Quarter-Final knockout stage.
Bangkok Metropolitan Administration FC beat Nakhon Si Thammarat FC in the final.
|Bangkok Metropolitan Administration FC||2 – 2|
|Amnat Charoen||2 – 2|
5 – 4 pens
|Bangkok Metropolitan Administration FC||2 – 0||Pathum Thani|
Bangkok Metropolitan Administration FC and Amnat Charoen advance to Quarter-Final stage.
|Phetchaburi||3 – 1||Pichit|
|Nakhon Si Thammarat FC||- – -||Ubon Ratchathani|
Nakhon Si Thammarat FC and Phetchaburi advanced to the next round
|Ayutthaya||5 – 2||Si Saket FC|
|Phitsanulok FC||3 – 3|
Ayutthaya and Phitsanulok FC advanced to the next round