Background: Reproductive life plan counseling (RLPC) is a tool to encourage women and men to reflect upon their reproduction, to avoid unintended pregnancies and negative health behavior that can threaten reproduction. The aim was to evaluate the effect of RLPC among women attending contraceptive counseling. Outcomes were knowledge about fertility and awareness of preconception health, use of contraception, and women's experience of RLPC. Material and methods: Swedish-speaking women, aged 20-40 years, were randomized to intervention group (IG) or control group (CG). Participants (n = 1,946) answered a questionnaire before and two months after (n = 1,198, 62%) the consultation. All women received standard contraceptive counseling, and the IG also received the RLPC, i.e. questions on reproductive intentions, information about fertility, and preconception health. Results: Women in the IG increased their knowledge about fertility: age and fertility, chances of getting pregnant, fecundity of an ovum, and chances of having a child with help of IVF. They also increased their awareness of factors affecting preconception health, such as to stop using tobacco, to refrain from alcohol, to be of normal weight, and to start with folic acid before a pregnancy. The most commonly used contraceptive method was combined oral contraceptives, followed by long-acting reversible contraception. Three out of four women (76%) in the IG stated that the RLPC should be part of the routine in contraceptive counseling. Conclusions: Knowledge about fertility and awareness of preconception health increased after the intervention. The RLPC can be recommended as a tool in contraceptive counseling.