Thailand's Foreign Minister, Surakiart Sathirathai, and the Burmese intelligence chief, General Kinyunt, have celebrated the laying of the first foundations of a new bridge that will link the two countries.
The two sides also discussed improving transport links between the two countries, and how to combat the trafficking of drugs across the border.
Ties between Burma and Thailand have often been strained, and there were fears last year that they would fight a full-scale border war.
But on Monday, amidst much pomp and ceremony, the two ministers celebrated the laying of the first stone of the new friendship bridge at Tachilek.
Thailand says an open border is crucial to regional trade
The bridge will be finished within the year, according to the Thai authorities who are paying for its construction.
The Thais hope that the increased trade which they expect the bridge will bring will help the whole region develop economically.
Local Thai businessmen and politicians who came to witness the ground-breaking ceremony were obviously delighted.
They expect the value of trade to increase tenfold in the next two years. It is already worth more than $10m a year, just at this checkpoint.
Both sides expect the bridge to strengthen bilateral economic ties between the two countries, and allow Thailand to tap into the markets of southern China.
The Thais certainly hope that the greater economic integration that the bridge is expected to bring will lessen the likelihood of the return to cross-border tensions.
But local Thai government officials are also privately worried that the bridge might encourage an increase in illegal trade, especially the flow of synthetic drugs, or methamphetamines, into Thailand.
Some 10,000 "ya ba" tablets were seized only three days ago, as they were being smuggled across the border.
Combating drugs was also extensively discussed by the Thai foreign minister and the Burmese intelligence chief.
After laying the foundation stone for the new bridge, Burmese officials took the Thai foreign minister on a helicopter tour of inspection along the border, to see for himself what the Burmese were doing to stamp out drug trafficking.