Ross's birthdate skips around a lot. For example, he was perpetually 29 for three seasons (season 3, 4, and 5) as he stated as such at least once per season.

However, if we go by the pilot information where he says "I'm 26 and divorced!" then he was born in 1967 (the pilot aired in 1994).

In "The One With the Fake Party," Rachel said that she was a "28-year-old cheerleader." That episode aired in 1998, which would mean that Rachel was born in 1969. And therefore, Ross is only a year or two older than Rachel, depending on their actual birthdays, which are also inconsistent in the series.

I think it sucks that we aren't able to know their exact birthdays... but once in season 1 joey and chandler wants to take ross to a knicks game on the same day he married or something to carol and they say: we got you tickets for the knicks with us! happy birthday! and ross says "my birthday was 7 months ago.." when was this? then gunther asks rachel once when is her birthday she say may 5th and then ross wants to tell his and starts a sentence with "mine is october..", but in season 9 when joey hits ross' face and they're in a hospital joey has to fill out the forms and he asks ross' birthday and he says december 18th! so, what do you think?

More: And of course in 1998 Rachel is 28 so according to this she was born in 1969 (like Jennifer Aniston in real life).. And when she and Monica are seniors Ross and Chandler are in college but which year? And Ross says in 1998 "I'm 29 and divorced twice or..? Something like that so he and Chandler must be like 1-2 years older than Rachel and Monica..