Background : Most hospitalized children will experience physical pain as well as psychological distress. Painful procedure can increase anxiety and fear of pediatric patients and their parents who do not have understanding logical of their disease and hospitalization. This study attempted to identify pain reduction in related to therapeutic intervention by age and environmental improvement. Methods : A total of 194 hospitalized children and their parents were investigated. Data collection period was 3 months from March to May 2004. Four instruments were used to collect the data : Faces Pain Rating Scale(FPRS), Heart rate, Oxygen saturation and Pain behavioral check list. The data were analyzed by a SPSS program and tested x2-test, t-test, ANCOVA. Results : 1. Age from 0 to 3, the Heart rate, FPRS, Oxygen saturation and Pain behavioral check list were significantly different in theraputic intervention group when compare to control group. 2. Age from 4 to 6, FPRS, Oxygen saturation and Pain behavioral check list were significantly different in theraputic intervention group when compare to control group. But the heart rate were not significantly different when compare to control group. 3. Age from 7 to 9, FPRS and Pain behavioral check list were significantly lower in therapeutic intervention group when compare to control group but Heart rate and Oxygen saturation were not significantly different when compare to control group. Conclusion : The results of this study concludes that most children experience acute pain during IV therapy and it can be reduced by age specific therapeutic intervention and by change of surrounding environment.