The object of this research is to examine U.S. data on cardiovascular disease and job conditions for associations similar to those recently obtained by these researchers in cross-sectional and prospective analysis of Swedish national data. Those findings confirmed the relationship between C.V.D. and psychosocial job characteristics using a previously untested model of job psychological strain development based on job decision latitude (low) and psychological job demands. The strength of the relationships are similar in magnitude to that found for serum cholesterol, blood pressure, smoking, and type-A behavior in the Framingham and Western Collaborative Group C.H.D. studies. These same job characteristics have been shown to be predictors of psychological strain symptoms in comparable U.S. and Swedish national surveys. We propose to examine five major U.S. data bases including information on job characteristics and C.V.D. or C.H.D.: the H.I.S. (1972), H.E.S. (1960-62); H.A.N.E.S. (1970-75), the Western Collaborative Study, and the Framingham Study. While data measuring job characteristics is generally weak in all existing large scale U.S. C.V.D.-C.H.D. data bases, the above surveys do contain either limited direct measures of the relevant job characteristics or detailed U.S. Census Occupational Codes (382 categories). These codes can be used to indirectly assess job condition impacts with the help of job characteristic-occupation data in three national U.S. working condition surveys (1969, 1972, 1977). The U.S. data bases also allow control for conventional risk factors (especially age, smoking, serum cholesterol, type A behavior and socio-economic status). It should be noted that our model, based on work environment conditions, represents an alternative psycho-social mechanism of disease development to that implied by current "Type A" behavior research (based on personality characteristics). Also, previous U.S. and Swedish findings based on the model have not substantially weakened when socio-economic status is controlled.