Grant Smith took a 30 yard free kick in the first half which he hit into the wall, but it rebounded out, but he was unable to get a good second touch, and the ball was cleared away.
Parkin, Smith and Roberts all went close in the first half, but never managed to look like they would score.
It was Walsall who took the lead on 44 minutes from a very tight angle in what was their first proper shot on goal. The goal was scored by Julian Joachim.
Sean O'Hanlon came close to getting an equaliser half way through the second half, but his header was cleared off the line, and away for a corner.
On 64 minutes 4 subs were bought on, one for Walsall, and Jerel Ifil, Andy Caton, and Rory Fallon for Swindon replacing David Duke, Christian Roberts, and Matt Hewlett.
On 70 minutes Rory Fallon came the closest so far of getting an equaliser when his header hit the bar, but he was unable to get to the rebound.
Andy Caton also came close a couple of times getting himself tackled in the box, and then Caton's shot was handled in the box on 84 minutes by Walsall Roper. Sam Parkin took the third penalty in the last 4 games, and scored to make it 1-1.
Mark Wright then scored the winner for Walsall in the final minute of normal time when Joachim came in on goal, but passed to Wright just has Evans was about to try and block is shot, so wright was able to score into the empty net.
Swindon did press forward in the 3 minutes of time added on, but Walsall held on for their win, and Swindon slip down to 12th ending any hopes of getting into the play off's for another season.
Overall it was a fairly average game which Swindon should have won, but although they seemed to have a lot more of the ball than Walsall they didn't create many chances in front of goal.