Background: In Japan, the number of asthma deaths has been gradually decreasing. However, in the management of asthma, there are still some problems originating from patient-related factors and iatrogenic factors, both of which should be further analyzed. Methods: We investigated clinical and background characteristics of 164 patients with asthma who were admitted to our hospital with acute exacerbations, by reviewing their clinical records. Results: Fifty-two patients had received long-term management (LTM) based on the guidelines (the LTM group), while 112 had not (the non-LTM group). In patients whose asthma severity had been intermittent (step 1), the proportion of severe and near fatal exacerbations was significantly higher in the non-LTM group than in the LTM group. However, even in the LTM-group, 23% of mild persistent (step 2) and 38% of moderately and severely persistent (step 3 & 4) patients had severe or near fatal exacerbations. In these patients, the peak expiratory flow rate significantly improved after discharge, and poor adherence was also significantly higher in the non-LTM group than in the LTM group. A multivariate analysis revealed that the factors associated with poor adherence were: 1) no history of previous admission due to asthma exacerbation; 2) the patient was male; and 3) the patient was young (<60 years). Conclusions: In the LTM group, re-evaluation of the actual severity of asthma and prompt treatment corresponding to the severity of disease should still be encouraged. In the non-LTM group, establishing countermeasures against factors causing poor adherence would be the next step in ensuring strong adherence with LTM.