The influence of mediterranean climate on the onset of myocardial infarction (MI) was investigated. The study comprised 1306 MI patients from the coastal part of Middle Dalmatia admitted to the two hospitals in Split in 1981-1987 period. Myocardial infarction incidence during south-wind was significantly greater then during north-wind (chi 2 = 5.6; < 0.05) as well as during all non-south-wind days (chi 2 = 11.6; p < 0.001). The coefficients of partial correlation show mild but still significant connection of MI incidence with increased air temperature (rt = 0.064; p < 0.05) and relative humidity (rh = 0.064; p < 0.05). Cross-correlation with shift also revealed mild connection of MI incidence with increased temperature within four days before and on the day of incident (r = 0.023-0.034; p < 0.05). The analysis of synoptical situations in the days with greatest number of MI's (4 to 6) ascertained the characteristics of unstable weather when passing atmospheric front caused a change in the type of weather. The results suggest that coronary patients should stay at home during the south-wind passing atmospheric front, avoid physical stress and take more often antianginal drugs.