Two goals from Grant Holt had put the visitors firmly in control but a blunder by goalkeeper Glyn Garner gave Chesterfield hope and Jamie Ward saved a point with his 12th of the season.
Shrewsbury will wonder how they ended up hanging on for a draw after looking in control for the first hour of a game that saw both sides play some flowing attacking football.
It was the visitors who looked dangerous on the counter and both Holt and Chris Humphrey had good chances in the first seven minutes.
Just when it seemed the first half would end goalless, Shrewsbury won a penalty when Holt was dragged down by Robert Page and the striker put the spot-kick into the top right corner.
Holt scored again in the 54th minute when Humphrey did well to pull the ball back from the right touchline and Richard Walker headed down for Holt to thump a shot into the top left corner.
That looked to be it for Chesterfield but the introduction of Darren Currie turned the game in their favour.
But it still needed a bad mistake by Garner, who palmed Currie's 25-yard shot into the net in the 67th minute, to throw the contest open again.
Shrewsbury lost their composure and it was no surprise when Jack Lester was tripped by Michael Jackson and Ward calmly converted the penalty.
Chesterfield might have won it in stoppage time when Lester's curling shot from just inside the area was brilliantly clawed away by Garner but it was a bitter-sweet night for the keeper whose mistake had let Chesterfield back in.