The visitors had come from behind and were seconds away from their third win of the campaign when Samp substitute Citadin Eder was fouled in the area and the referee pointed to the spot.
Eder made no mistake to earn his team a vital point.
Ciro Immobile had previously cancelled out Gianluca Sansone's 41st-minute opener before Alessio Cerci converted a penalty to put Torino ahead in the 76th minute.
Samp, whose coach Delio Rossi was given a vote of confidence ahead of the game by club president Edoardo Garrone, are still in the relegation zone with just three points from seven games.
Toro went into the contest looking to bounce back from last weekend's 1-0 defeat against Juventus in the Turin derby.
However, they failed to test Sampdoria goalkeeper Junior Costa in the first half.
Sampdoria's Sansone was the first to threaten in the 13th minute with his right-footed shot from 12 yards forcing Torino goalkeeper Daniele Padelli to make his first save.
The hosts continued to push forward and on the half-hour mark, Padelli kept out Pedro Obiang's bullet strike that was heading to the far post.
Samp's efforts paid off before half-time when a counter-attack saw Angelo Palombo set up Sansone just outside the area and his left-footed strike beat Padelli.
Torino showed more determination after the break and drew level in the 66th minute following a corner kick.
The ball fell to Immobile, who smashed a right-footed shot from the heart of the area past Costa for his first goal of the campaign.
The visitors, with the wind in their sails, went ahead 10 minutes later.
The referee pointed to the penalty spot after Palombo brought down Danilo D'Ambrosio in the area.
Cerci coolly struck the ball towards the bottom right corner of goal and out of Costa's reach.
Eder had the last say after he was fouled by Kamil Glik in the box.
He struck his spot-kick past Padelli and into the bottom right corner of goal to earn Sampdoria a share of the points.