Background Psychosocial factors have been reported to be independently associa ted with coronary heart disease. However, previous studies have been in mainly N orth American or European populations. The aim of the present analysis was to in vestigate the relation of psychosocial factors to risk of myocardial infarction in 24 767 people from 52 countries. Methods We used a case control design with 11 119 patients with a first myocardial infarction and 13 648 age matched (up t o 5 years older or younger) and sex matched controls from 262 centres in Asia, Europe, the Middle East, Africa, Australia, and North and South America. Data fo r demographic factors, education, income, and cardiovascular risk factors were o btained by standardised approaches. Psychosocial stress was assessed by four sim ple questions about stress at work and at home, financial stress, and major life events in the past year. Additional questions assessed locus of control and pre sence of depression. Findings People with myocardial infarction (cases) reported higher prevalence of all four stress factors (p < 0.0001). Of those cases still working, 23.0%(n=1249) experienced several periods of work stress compared wit h 17.9%(1324) of controls, and 10.0%(540) experienced permanent work stress du ring the previous year versus 5.0%(372) of controls. Odds ratios were 1.38 (99 %CI 1.19-1.61) for several periods of work stress and 2.14(1.73-2.64) for per manent stress at work, adjusted for age, sex, geographic region, and smoking. 11 .6%(1288) of cases had several periods of stress at home compared with 8.6%(11 79) of controls (odds ratio 1.52 [99%CI 1.34-1.72]), and 3.5%(384) of cases r eported permanent stress at home versus 1.9%(253) of controls (2.12 [1.68-2.6 5 ]). General stress (work, home, or both) was associated with an odds ratio of 1 . 45 (99%CI 1.30-1.61) for several periods and 2.17 (1.84-2.55) for permanent s tress. Severe financial stress was more typical in cases than controls(14.6%[1 6 22] vs 12.2%[1659]; odds ratio 1.33 [99%CI 1.19-1.48]). Stressful life e vents in the past year were also more frequent in cases than controls (16.1%[1790] v s 13.0%[1771]; 1.48 [1.33-1.64]), as was depression (24.0%[2673] vs 17. 6%[24 04]; odds ratio 1.55 [1.42-1.69]) . These differences were consistent across re gions, in different ethnic groups, and in men and women. Interpretation Presence of psychosocial stressors is associated with increased risk of acute myocardial infarction, suggesting that approaches aimed at modifying these factors should be developed. Background Psychosocial factors have been reported to be independently dependentia ted with coronary heart disease. However, previous studies have been in primarily N orth American or European populations. The aim of the present analysis was to in vestigate the relation of psychosocial factors to risk of myocardial infarction infarction in 24 767 people from 52 countries. Methods We used a case control design with 11 119 patients with a first myocardial infarction and 13 648 age matched (up to 5 years older or younger) and sex matched controls from 262 centers in Asia, Europe , the Middle East, Africa, Australia, and North and South America. Data fo r demographic factors, education, income, and cardiovascular risk factors were o btained by standardized approaches. Psychosocial stress was assessed by four sim ple questions about stress at work and at home, financial stress, and major life events in the past year. Additional questions assessed locus of control and pre sence of depression. with those myocardial infarction (cases) reported higher prevalence of all four stress factors (p <0.0001). Of those cases still working, 23.0% (n = 1249) experienced several periods of work stress compared wit h 17.9% (1324) of controls, (540) experienced permanent work stress du ring the previous year versus versus 5.0% (372) of controls. Odds ratios were 1.38 (99% CI 1.19-1.61) for several periods of work stress and 2.14 (1.73-2.64) for per manent stress at work, adjusted for age, sex, geographic region, and smoking. 11 .6% (1288) of cases had several periods of stress at home compared with 8.6% (1179) of controls (odds ratio 1.52 [99 % CI 1.34-1.72]), and 3.5% (384) of cases r eported permanent stress at home versus 1.9% (253) of controls (2.12 [1.68-2.6 5]). General stress (work, home, or both) was associated with an odds ratio of 1. 45 (99% CI 1.30-1.61) for several periods and 2.17 (1.84-2.55) for permanent sress. Severe financial stress was more typical in cases than controls (14.6% [1 6 22] vs 12.2%; odds ratio 1.33 [99% CI 1.19-1.48]). Stressful life e vents in the past year were also more frequent in cases than controls (16.1% [1790] vs 13.0%; 1.48 [1.33-1.64]), as was depression (24.0% [2673] vs 17. 6% [24 04]; odds ratio 1.55 [1.42-1.69]). These differences were consistent across re gions, in different ethnic groups, and in men and women. Interpretation Presence of psychosocial stressors is associated with increased risk of acute myocardial infarction, suggesting thatiors aimed at modifying these factors should be developed.