The aim of this work was to find out whether there is any relationship between the climate in Rosario City, Argentina, and the frequency of asthmatic crises, and whether it would be possible to use weather forecasts to support therapeutic measures. Synoptic and statistical metereological analyses, were used, and the following results achieved: The 721 crises of asthma developed in Rosario City between August 1, 1978 and July 31, 1979, demonstrated the well-known seasonal distribution of similar biological events: high frequencies in the Spring and Fall and low ones in the Summer and Winter. Important correlations were found with high altitude depression systems Hence, in the great majority of cases, the daily frequency of crises attained its maximum values when a depression system in the 500 mb. level was approximately between 60 degrees and 72 degrees W of G. and returned to minimum values when the mentioned system, in its general displacement towards the east, passed the meridian of Rosario City, whose geographic coordinates are: Lat. 32 degrees 55' S, Long. 60 degrees 47' W of G., at 27 meters above sea level. In short, we can say that, as occurs in other parts of the world, the asthmatic crises undergone by children in Rosario City are produced with much more frequency in circumstances of cyclonic atmospheric circulation. Although these situations, in the case of Rosario City, are determined by the dynamic processes in the higher levels of the troposphere. This is probably due to the role played by the Andres Mountain Range in the processes of atmospheric circulation in subtropical South America.(ABSTRACT TRUNCATED AT 250 WORDS)