We evaluated the cost-effectiveness and budget impact of a suicide helpline in Belgium, consisting of a telephone- and a chat service. An age- and gender-dependent Markov model with a ten-year time horizon and a one-year cycle length was developed, assuming a societal perspective, to predict cumulative costs and quality-adjusted life-years (QALYs) in the helpline users. The model included six transition states: the initial state (at risk), first attempt, re-attempt, follow-up, suicide and death from other causes. Data on the effect of the helpline and costs associated with model states were obtained from the literature. One-way and probabilistic sensitivity analyses were performed to capture uncertainty. In addition, the budget impact of the helpline was analysed. Over ten years, the telephone- as well as the chat service could avoid about 36% of suicides and attempts in this high-risk population. In males, 0.063 QALYs (95% confidence interval, CI 0.030-0.097) and 0.035 QALYs (95%CI -0.026-0.096) were gained by users of the telephone- and chat service respectively. The corresponding values for females were 0.019 QALYs (95%CI -0.015-0.052) and a QALY-neutral result of -0.005 (95%CI -0.071-0.062). There were net societal savings of respectively €2382 (95%CI 1953-2859) and €2282 (95%CI 1855-2758) in male users; €2171 (95%CI 1735-2664) and €2458 (95%CI 1945-3025) in female users. At the population level, an investment of €218,899 saved €1,452,022 for the public health service (national health insurance), mainly due to the telephone service. The analysis predicted that both means of telemedicine for suicide prevention in Flanders are cost-saving, and have a modest effect on QALYs.