Some of the "traditional" original air dates shown on this site have been found to be in error and have been revised with a link to this page. The ultimate source of the traditional dates is unknown but may have been the originally scheduled broadcast dates. It looks like the schedule may have been tweaked to air the best episodes during the Fall Nielsen ratings periods.
Since this site is strongly dependent on episode numbers, the sequence of the episodes will not be changed to match the revised dates. As far as I can tell, the listed order matches the order episodes were broadcast in syndication.
The traditional air dates were obtained from The Perry Mason TV Show Book by Brian Kelleher and Diana Merrill (1987). The IMDb is currently using these dates as well.
Later books, Perry Mason - The Authorship and Reproduction of a Popular Hero by J. Dennis Bounds (1996), and Raymond Burr - A Film, Radio and Television Biography by Ona L. Hill (1994), also have dated lists of episodes. Their degree of agreement is noted below.
The observed air dates have been determined by checking television listings in newspapers of the time at the Newspaper Archives.
The partial set of episodes broadcast in syndication on The Hallmark Channel (2002-2004) were in the sequence of the traditional air dates. This was also true for a smaller set of episodes broadcast on a local television station some years before.
Initial research reveals that #48, TCOT Purple Woman, was originally aired two weeks earlier than the traditional date. No other episodes were affected. Both the Bounds and Hill books have the observed date.
from Season 2
|#48||TCOT Purple Woman||12/06/58||11/22/58|
Additional research reveals that #157, TCOT Double-Entry Mind, was originally aired two weeks later than the traditional date. This shift caused #158, TCOT Hateful Hero, and #159, TCOT Dodging Domino, to each air a week before their traditional dates. This may have been to position one of the shows for the Nielsen's "mid-October" ratings survey released on 11/06/62. The Bounds book has the observed dates. The Hill book has the traditional dates.
from Season 6
|#157||TCOT Double-Entry Mind||10/18/62||11/01/62|
|#158||TCOT Hateful Hero||10/25/62||10/18/62|
|#159||TCOT Dodging Domino||11/01/62||10/25/62|
David Sadowski noted in the Perry_Mason Yahoo! group that #185, TCOT Deadly Verdict, was originally aired two weeks ahead of the traditional date possibly so it would be included the fall Nielsen ratings survey. This schedule shift caused #183, TCOT Shifty Shoe-Box, and #184, TCOT Drowsy Mosquito, to each air a week later than their traditional air date. Both the Bounds and Hill books have the observed dates.
from Season 7
|#183||TCOT Shifty Shoe-box||10/03/63||10/10/63|
|#184||TCOT Drowsy Mosquito||10/10/63||10/17/63|
|#185||TCOT Deadly Verdict||10/17/63||10/03/63|