The former Chelsea striker has been linked with a number of Championship clubs and his goal in the 12th minute could well be his last for the Robins.
Going into this game, both sides were assured of safety in League One and the encounter had a distinct end of season feel about it.
Swindon started the brighter and almost grabbed the lead within five minutes when a Grant Smith volley was headed off the line by Chesterfield captain Ian Evatt.
Swindon, though, only had to wait seven minutes before Parkin broke the deadlock. The Scotland striker rose to meet Kyle Lapham's cross to head low into the Chesterfield net.
Swindon then failed to capitalise on all their early possession and Chesterfield consequently drew level.
A long throw was not dealt with and Tcham N'Toya-Zoa came away with the ball to fire off the post and into the Swindon net for his eighth of the season.
Both sides seem to start the second half well below par with players' minds perhaps on their summer holidays.
Apart from a Smith header which sailed over the bar and a Michael Pook effort which was wide, neither team seemed interested in securing the three points.
The only real excitement of the half came when Chesterfield's N'Toya-Zoa sparked the Swindon crowd into life with some amateur dramatics in the penalty area.
The French striker thought he had earned his side a penalty but his appeals were promptly waved away by the referee.