It was signed by 84 high school students.
Four of the signatories at the news conference on Monday said they were aware that refusing to enlist would land them in jail, but noted that they were acting out of loyalty to their values and those of the society they live in.
"We were born into the reality of the occupation and many in our generation see it as something 'natural'," Or Ben-David, a 19-year-old from Jerusalem, said.
Ben-David is legally obliged to join the army at the beginning of November.
"But I opened my eyes to what was around me and became critical of the Israeli society. I visited in the West Bank and met with Palestinians, it changed my view of things."
When asked whether she would do a different kind of public service, another refusenik - Amelia Marcovich - said she considered public service and volunteering to be a lifelong activity and not just something that you do for two or three years because you have to.
"I hope that sitting in jail won't dampen my desire to contribute to the society and that I'll keep on volunteering afterward," she said.
Another objector, Effie Brenner, a student, said he is refusing against his parent's wishes. "My parents reacted really badly when I told them I wouldn't join the army. They threatened to kick me out of house," he said.
Nevertheless, he said it was easier to do three years of military service than to stand up and make a statement and even sit in prison for what you believe in.
"One of the reasons I refuse to join is because I want the Palestinians to know that not all Israelis are in favour of the occupation and that some people are willing to make a sacrifice to end it," Brenner said.
"Palestinians who have heard of what I'm doing have expressed thanks and encouragement."
Brenner said the group had already employed legal representation and they were ready to face the military trials awaiting them.
Similar letters have been publicised over the years by high school seniors slated to enlist ever since the first one was written in 1979.