The Cobblers had leaked four second-half goals against Barnet but they were solid and determined at Chesterfield, who were restricted to only a couple of chances.
Both fell to substitute Colin Larkin but he could not find the target and the visitors might have snatched victory but for a fine save by Barry Roche early in the second half.
The conditions on a raw windy night were difficult but the quality on display was poor with both teams giving the ball away far too often.
The first half contained few incidents of note apart from an injury to Chesterfield striker Caleb Folan who left the action in the 22nd minute after a collision with Mark Bunn.
Larkin replaced him and was presented with a chance immediately when Kevan Hurst crossed from the left but the striker completely mis-timed his header with only Bunn to beat.
Northampton had few openings before the interval but they were brighter in the second half and midfielder David Hunt was close to opening the scoring with a right-foot shot from the edge of the area which struck Roche on the legs before bouncing to safety.
Hunt saw another long-range effort go just wide and Chesterfield were denied by an offside flag in the 64th minute after Larkin sprinted clear.
Northampton continued to defend strongly but they were beginning to pose questions to the home defence and in the 70th minute Chris Doig headed a free-kick down to Scott McGleish who could not get the ball out from under his feet and he was crowded out.
The introduction of Wayne Allison was always likely to pose a threat in the air and in the 71st minute the veteran striker met a corner with a powerful header at the back post but Andy Holt leaped athletically to head off the line.
The match was beginning to open up and Andy Kirk was only just wide after a strong run from just inside his own half, but it was Chesterfield who came closest to scoring in the final minutes.
When Northampton gave away a free kick 25 yards out, Hurst lined the ball up and curled a shot over the wall but Bunn dived to his left to palm the ball away.
The corner was cleared but there was another moment of danger in the 84th minute when Paul Hall found some space on the right and delivered an excellent cross which Larkin glanced narrowly wide.
But Northampton kept their shape and discipline to take a deserved point and leave Chesterfield regretting the two missed chances and waiting on the fitness of Folan.