Intradiurnal fluctuations in the airborne pollen count of nine of the taxa which are most important in the atmosphere of Málaga (SE Spain) were studied. A mathematical formula, the “intradiurnal distribution index”; (IDI), permitted an accurate numerical comparison of the different years and taxa studied. Sampling was carried out during the period 1992–1995 with the aid of a Burkard volumetric spore trap. Although on the basis of the IDI values obtained, three types of behaviour were distinguished, most taxa showed maximum concentration peaks around midday.