The aim of the study was to investigate the relationship between mortality from cardiovascular diseases (CVD) and socioeconomic status (SES) in Sweden and to estimate to what extent the difference between a province with low mortality and the rest of Sweden was dependent on socio-economic factors. A population-based retrospective study with a historical prospective approach was performed covering a 10-y period in the province of Halland, Sweden, as well as Sweden as a whole. Altogether 1654 744 men and 1592 467 women were included, of whom 45 394 men and 43 403 women were from Halland, distributed according to SES. Multivariate analysis with Poisson regression was used. Relative risks with 95% confidence intervals were calculated. Both men and women with a low SES showed a significantly higher risk of death from CVD in Sweden as a whole. The risk was 23% higher for male blue-collar workers and 44% higher for female blue-collar workers when compared to their white-collar counterparts. The level of mortality in Halland was 14% lower compared to the country as a whole when only age was taken into account. When the socio-economic variable was also included, this figure was 8%. The results show the substantial significance of social differences with respect to CVD mortality. The effect of SES seems to be more important than that of geographical conditions when the latter are isolated from socio-economic influence.