Why is it rated-R?

I haven't seen this movie in a long while, probably not since it came out on theatres. But I don't remember any nudity. Just him tearing off parts of clothes from some females. It may have showed some underwear, but that's it.

Otherwise I guess the "R" rating is due to the story. Not much actual violence was shown either. Just hinted at.

Compared to movies which are rated R these days, no, it doesn't deserve an R. Remember, this movie was made in the early days of the movie rating system. If it were made today, it would probably be PG-13, and would seem pretty tame compared to others which are PG-13 at that. Flashes/suggestions of nudity, most violence implied, and adult subject matter. Very minimal "adult" language.

Probably for the scene with Sally Kellerman as Diane Cluny. I don't recall there being any actual nudity shown, but it's pretty clear he made her strip naked and lie on the bed while he slowly and methodically shreds her nightgown and uses the strips to tie her spreadeagle to the bed by wrists and ankles. It was a pretty intense scene that ends when she decides to fight back before he ties her last free arm to the bed. She fights back and screams loudly, he tries to muffle her screaming with his hand and she bites it, and for his part he punches her in the face leaving her black and blue, but has to flee because her screams have alerted other apartment dwellers nearby to call the police.

Other than that, there was one brief scene early in the movie where he grabs a victim from behind possibly seeming to fondle her breasts through her shirt (or he might just be holding her tightly). Then it's implied that he pulls the shirt off but again I don't recall any nudity shown, and it was over very fast.

Most of the other scenes just show dead victims - and most of the time, not even the victim's face, just a pair of legs lying there.

I also caught a version of this edited for TV once; they cut out most of the racy stuff in the Cluny scene, although aspects of it are revealed in flashback when the psychiatrist is examining De Salvo. That version has less intensity than the uncut R version.

The strangler gets some flashbacks of the 11th (or was it the 12th?) victim, the one he killed during Kennedy's funeral, lying naked with her wrists tied up, when the character played by Henry Fonda is interrogating him. You can only see her breasts for a few seconds.

They had just come off the "M" for Mature rating system & were still using some of the codes from that. But it was given the "R" rating for what was considered Explisit Language, Sexual Content, Brief Nudity & Violence for Its Era. The "F" word had only been used in a limited fashion in Films during this era, so just the use of what today is thought of as common vulgarities in Film would have been reason enough for the "R" rating then. Even today using what can be considered an Excessive amount of common vulgarities will still get an "R" rating, instead of "PG".

Just watched this film today. There are brief flashes of breasts, but the R rating would be otherwise mainly due to its frank dealing with sexual perversion, mainly in the language of the characters. There is little or no actual profanity, but in 1968 the tone of the film would have been very much worth an R rating. Today it would probably be PG-13.

Today it would be PG-13. The person was right about the gay characters and the use of language referring to them. Automatic R in '68, when the ratings system was brand new and put in place for just this type of "stuff."

How old is your daughter. It isn't graphic by today's standards but certainly not for kids.