All my life. It just took me 21 years to realize it.

All my life, I was not an out spoken atheist until I turned 22 however.

Agnostic for about 48 years.

Athiest for 50 years.

Not too long in the grand scheme of things. I desperately wanted there to be an all knowing deity. But about 7yrs ago with the help of a couple of my kids I put 2 and 2 together and finally got 4 instead of "purple... I'm a bit ashamed that it took so long, I'm 55.. it's been one of the most satisfying things in life... guilt has always been crushing for me....

I think I started becoming "Agnostic" in 1981, but then I would try to go back believing what I did under circumstances. I was always trying to put Christianity under Objective Issues ever since. I just think they want all the Credit for things. Life is about what we want to make it to be.

Since I was 14, in 1970. Was sitting in a baptist church listening to the man screaming that we were sinners and I just knew. That was the end of it for me. Very profound moment, like a light switch turning on.

Hard to pinpoint exactly how long, but I read the Oxford History of Christianity and had complete understanding about 1985, I don't think the book intended this outcome but it was very factual and atheism made sense after.

Honestly, I have been an atheist for decades. But growing up in the Bible Belt I didn't think that not believing was an option. I was raised Southern Baptist/ Pentecostal. After I realized I didn't believe, I went through looking at a number of other religions including Wicca. I found that I liked their tenets, which were very progressive, but didn't believe in the magical aspects of it. At that point I decided that I could hold whatever tenets that I wanted to and didn't need the religious/faith aspect of it or any other religion.

About 6 years now or so. I had been heading towards atheism for a long time before I finally took the plunge though. The switch that finally set it off about watching a play (entitled: On Ego) about the human mind and teleportation (Star Trek style, through dematerialization). That play got me thinking about whether or not I believed in a soul and I started googling "evidence for souls" and eventually landed on debates by Dawkins, Hitchens, and other atheists which sealed the deal. By the end of October my freshman year I was an atheist.

Since 1995

Since day one. Never went to church and my parents were Atheist and Agnostic.

A very long time. I grew up Roam Catholic but never bought into the stuff they were teaching and preaching (look at me I am a poet and don't know it). Now I see all those in the business of religion as conmen like our current President and I see believers are having a mental problem.

I've been an agnostic/atheist since I studied philosophy in undergrad, it has now been about twenty-five years.

I think pretty much all my life.

I was actually raised Seventh Day Adventist, and began 'doubting' when I was ~13. I worked out the circular logic that 'proves' the Bible is the word of God (because the Bible says it is), and went to talk to our youth pastor about this problem, and when I realized his only answer boiled down to 'ask God', and relied on my being sufficiently brainwashed to interpret subtle and probably nonsense physiological or psychological cues as messages from God, I quit the Church. No one has ever provided a better argument to convince me to return to believing in a God, let alone in the Bible, and I've never been tempted to return to believing in religion since. Since I am 38 now, I guess that means I've been an atheist for 25 years.

since birth

I guess since sometime in high school, although I didn't actually hear the term 'agnostic' until college, and I then started identifying as agnostic. In the last 5 years or so, I've started following agnostic/atheist sites, and I now identify as atheist.

Officially about 5 years. I grew up in a Christian household and was raised to believe in God and just blindly believed because as a kids that's what you do. You believe what you're parents tell you. Up through college I believed then slowly lost my faith as I learned more and more about life, science, and the world. Then a close friend died at the young age of 22 and it made me seriously question everything. Then another close friend of mine who is agnostic helped me see the truth more clearly and I haven't looked back.

3 years

I have been a non believer since I was ten or eleven. When introduced to science it did not make sense to me (Bible). I could not accept the stories as real. I found to many situations that strayed from the Bible and were accepted as OK.

only 1 year

16 years. I was still going to a private protestant school when I realized Christianity was bullshit and never wondered if any of the other world religions might be the true faith.

35 plus years

As a young child I wanted to believe and wished my mom (who had religious beliefs) took me to church on a regular basis so I would fit in with other children in school. I think in later elementary and middle school I read parts of the bible and questioned what it said and tried to reconcile what I was told and what I was reading. I never felt comfortable "praying" or saying anything about God from high school on...when my children were born I wanted to give them the option to believe or not. As a young adult I did not believe and I became more comfortable with my agnostic and now atheist beliefs in my 40's. All three of my children are accepting either though they are at different levels in their believe in God-Love them and respect their ideals.