Rovers' £8million pound signing Jordan Rhodes looked to have secured the points for the away side with a crisp volleyed effort in the 34th minute, but the Rams snatched a deserved equaliser when Robinson bundled home from point-blank range.
A share of the spoils continues Blackburn's unbeaten away record in the npower Championship, but the expensively-acquired squad have now gone five games without victory.
Black boldly opted to relegate captain Danny Murphy to the bench, with David Dunn returning in the centre, with Derby unchanged from their goalless draw against Brighton last time out.
The opening exchanges were largely unremarkable, although Blackburn's passing was awry early.
Dead balls appeared their likeliest route to goal, Morten Gamst Pedersen twice causing problems with curling free-kicks from the left side of the area.
Richard Keogh dealt with the first one well but the second, in the 21st minute, was powerfully met by Scott Dann, whose header needed a strong save from Adam Legzdins.
Three minutes earlier Robinson had a good chance for the hosts, getting on the end of James O'Connor's cross at the far post but not managing a firm enough connection.
Back-to-back Derby corners caused problems, Jake Buxton's header diverted wide by Dann and Robinson's effort nodded high and wide.
Blackburn rallied and began to dictate matters in midfield and another free-kick, this time from the right, saw Pedersen draw a full-stretch save from Legzdins at the top corner.
In the 34th minute the visitors took the lead, Colin Kazim-Richards chipping towards Pedersen, whose cushioned header found Rhodes in support.
The Scotland striker waited for the ball to drop then fired home first time from 20 yards.
Bradley Orr, breaking forward from right-back, had two chances for Blackburn before the break but failed to add to the lead.
It took just 40 seconds of the second half for Rovers to go close again, Martin Olsson surging down the left wing and cutting back for Rhodes, who was desperately close to adding the finishing touch.
Derby were not giving up hope yet and fashioned a fine chance of their own when Jeff Hendrick's cross found Bryson 10 yards out.
The midfielder could not keep his snap shot down but the warning had been served.
Hendrick and Bryson both shot over in quick succession and Paul Coutts curled an ambitious effort on to the roof of the net as the Rams grabbed the initiative.
Derby continued to press without success, Buxton rising to meet a 66th-minute corner but missing the target.
Nigel Clough made the curious decision to move from 4-4-2 to 4-5-1 for the last 15 minutes, Conor Sammon departing to leave Robinson alone in attack.
Clough eventually remedied that by sending Nathan Tyson on and he drew a smart save from Paul Robinson within moments of coming on.
Derby were committing more men forward now and as Blackburn counter-attacked Mauro Formica went close to curling in his side's second from 25 yards.
The equaliser arrived in the 89th minute, the energetic Bryson drilling low and forcing an impressive save low from Robinson.
Unfortunately for Rovers the ball squirmed to Robinson and he converted, via Robinson, from a tight angle.