The announcement came at 9pm on Tuesday, three hours after the toss was scheduled for at the Mirpur Sher-e-Bangla National Cricket Stadium.
The sharing of the trophy, however, appears to be frustrating for the hosts who were out to regain pride after conceding loss in the one-off Test and the first match of the T20 series against Afghanistan.
The Afghans, still tournament favourites after two consecutive defeats that ended their record 12th T20I wins in a row, may not be happy as well.
The groundsmen were yet to start work and finally the umpires decided to abandon the match seeing little or no chance of the field being dried even if rain stopped.
With rain in the forecast, the day was cloudy and the downpour started around 5pm.
Thousands of fans braved rain to enter the stadium. Their wait for hours finally ended with the announcement when the galleries were still occupied by more than 15,000 spectators.
Bangladesh have topped the points table despite losing the first match to Afghanistan. The hosts reignited hopes by winning the second clash just before the final.
Skipper Shakib Al Hasan regaining his mojo with the bat was the best thing happening to the Tigers foung into the final game against their South Asian neighbours as the cricket rivalry between the two teams is developing.
His masterly 70 saved the Tigers in the match, taking them to the brink of their first win in T20I series involving more than two teams after they won the first such One-Day International series in Ireland in May.
Recently appointed Head Coach Russell Domingo acknowledged that they haven't found their perfect game yet and the final will be the perfect time for that
Afghan captain Rashid Khan was doubtful for the finale after picking a hamstring injury in the last tie, their first T20 loss to Bangladesh in five matches.