Organizations are confronted with a constant need for efficiency, which affects the working atmosphere, often typified by velocity, time pressure, competition, job insecurity, and information overload, which may lead to stress, burnout, work-life disbalance, and lowered work functioning. This study evaluated an 8-week, 1.5 h-per-week group-based standardized mindfulness program (BFinding peace in a frantic world^), applied on-site in a large multinational company. In a naturalistic longitudinal design self-selected employees (n = 150) completed measurements at wait-list, pre-test, post-test, and 2 and 6 months follow-up. Nearly all participants followed at least five out of eight sessions, were highly satisfied with the training (8.3 out 10), and almost 90% intended to continue with mindfulness practices. Primary outcomes were stress and risk for dropout from work. Using multilevel analyses, mean pre-test scores were compared to the other measurement occasions, and the rate of change in the training period (M = 67 days; SD = 12) was compared to the rate of change in the wait-list period (M = 29 days; SD = 8). Direct and long-term positive effects on risk for dropout from work (p < .001; effect size (ES) = 0.67, 0.73, and 0.88, respectively) and stress (p < .001; ES = 0.72, 0.86, and 1.02, respectively) were found. The risk for dropout from work declined from 54.4% at wait-list (45.8% at pre-test) to 16.4% at 6 months follow-up, and declined significantly faster (p < .001) during the training than during the wait-list period, but stress did not. In addition, positive effects on secondary measures of psychological well-being and functioning at work were found. In conclusion, a standardized mindfulness training in a multinational company reduces stress and risk for dropout and improves well-being and functioning at work, also in the long term, but a comparison of the training against alternative stress-reducing interventions is needed. Keywords Mindfulness. Well-being. Business world Companies and their employees are confronted with continuous transformation, globalization, growing cultural changes, and a constant need for efficiency (e.g., Houtman et al. 2007). This influences the work atmosphere, which is often typified by velocity, time pressure, competition, job insecurity, and facing an overload of stimuli on a daily basis. Constant availability has become a defining characteristic of our work situation, primarily due to social media and modern telecommunication. Work-related pressure is the main source of stress in the USA, representing a serious threat to employee health and well-being (Aikens et al. 2014). A significant number of people state that stress has a very strong negative impact on their physical (25%) or mental health (28%) (APA 2015). Between 2009 and 2014, the number of sick days due to serious mental health complaints has doubled; in the UK, 70 million sick days, which is more than half of the total of the annual 130 million sick days, are due to mental health problems such as stress, depression...