The study examined the effects of a short-term web-based mindfulness program. Participants describing themselves as stressed were recruited and a total of 70 participants were randomly assigned to a treatment group (n=35) and a control group (n=35). The mindfulness program included two, 10-minute exercises per day, six days a week, for two weeks. Twenty participants in the treatment group and 34 participants in the control group completed the training. The mean pretest scores indicated that the group was above the cutoff for severe stress on a wellestablished measure (the Perceived Stress Questionnaire). Measures of stress, anxiety and depression symptoms, and a mindfulness questionnaire were administered before, during (after 1 week), and at the end of the treatment (after 2 weeks). The results showed that mindfulness training increased mindfulness skills and reduced levels of perceived stress, anxiety, and depressive symptoms (Cohen’s ds>1). No significant changes from pre- to posttest were observed in the wait-list control group. Additionally, increments from pre- to post-test in mindfulness skills were associated with reductions in symptom scores, indicating treatment-specific effects. Together, the results suggest that the brief webbased mindfulness program may serve as an effective means to treat individuals suffering from stress, and motivate further research involving active control groups, alternative forms of web-based treatments as a control, and long-term follow-up of the effects.