. Suryaningsih, E. and A.W.W. Hadisoeganda. 2007. Control Measure for Important Pests and Diseases of Hot Pepper by Applying Biorational Pesticide. The side effects of the overuse of synthetic pesticides on pepper cultivation have been detected in various locations. The use of other pesticide, such as biorational pesticide could reduce the quantity of synthetic pesticide application. A field experiment was conducted at farmers's field in Rancaekek (elevation 650 m), Bandung, West Java, from July 2001 to February 2002. A randomized block design with 4 replications was employed in this experiment.The treatments were biorational pesticide agonal 866 (crude extract mixture of A. indica 8 parts + A. nardus 6 parts + A. galanga 6 parts), TdNt 102 (mixture of T. diversifolia 10 parts + N. tabacum 2 parts), TdMa 106 (mixture of T. diversifolia 10 parts + M. azedarach 6 parts), tigonal 1066 (crude extract mixture of T. diversifolia 10 parts + A. nardus 6 parts + A. galanga 6 parts). The treatments were applied at 4 and 7 days interval. Synthetic insecticide pirethroid 2.5 EC 0.2% and propineb 70 WP 0.2%, both applied at 7 days interval. During the experiment, the most prevalent pests and deseases were C. capsici, C. gloeosporioides, T. palmi, and A. gossypii, respectively. The results of the experiment indicated that all of the biorational applied were as effective as synthetic pesticides in controlling pests and diseases of pepper with varying degree of efficacy. The most effective in controlling C. capsici were biorationals which contain A. indica component, while biorationals with T. diversifolia as a component seem to be much more effective in controlling C. gloeosporioides as well as T. palmi, respectively. On the other hand, biorationals with M. azedarach and N. tabacum component were found to be as effective as synthetic insecticide pirethroid 2.5 EC 0.2% in controlling T. palmi and A. gossypii. The results of the experiment showed that biorational pesticides can be used to replace synthetic pesticide in controlling important pests and diseases on pepper.