In this paper we report results of skin prick tests (SPT) using pollen extracts on 200 patients with clinical symptoms of asthma, and results of a parallel study in which pollen was collected and classified over a period of 18 months. The patients were outpatients from the University Hospital in Kuala Lumpur, Malaysia, while the pollen grains were collected with a spore trap placed in the campus of the University of Malaya, approximately one kilometer from the University Hospital. Pollen extracts of 3 grasses (Bahia, Bermuda, rough pigweed) and 2 flowering trees, Acacia and Melaleuca, were used in the SPT. Of the 29.5% asthmatics with positive SPT reactions, 21.5% were to one or more of the grass pollens, 21.5% to Acacia and 7.5% to Melaleuca pollen. Acacia and Bermuda grass extracts were the most allergenic, which agreed with results of the pollen collection which showed grass and Acacia pollen grains to be the two most commonly found pollens.