Abstract. Mawazin, Octavia D. 2018. Eradication test of Acasia crassicarpa in peat forest. Pros Sem Nas Masy Biodiv Indon 5: 324-329. Acacia crassicarpa is classified as a fast-growing tree species which is the main species in building industrial plantations on peatlands which have an invasive potential. Eradication tests were carried out on A.crassicarpa plants that had grown wildly in the peat land natural forest areas which were located in Tasik Besar Serkap Forest Management Unit (FMU/ KPH) and bordered by A. crassicarpa industrial plantations. The eradication method was carried out by cutting plants, peeling bark, cutting bole followed by polishing stump with active ingredient of triclopyr 4.8 g/L, and cutting bole without polishing stump. The eradication application is carried out at the beginning of the dry season in April to minimize the growth of new branches or shoots from trees that have been cut down. The eradication technique of extracting the crassicarpa seedlings was carried out on tillers that had a diameter of less than 7 cm, and a diameter of more than 7 cm should be carried out by another technique because extraction would not be possible (unplugged). At 6 months after the eradication application was obtained the results of the effectiveness of eradication techniques in controlling A. crassicarpa were100%, 93.3%, and 73.3% respectively for eradication treatment which was cut down and immediately smeared with chemicals; eradication by skin stripping techniques; and eradication which was only done by logging. Eradication of A. crassicarpa by logging has the lowest effectiveness because some of the trees cut down will sprout again. The physical and chemical combination eradication techniques (cut down and smeared with active ingredients) produce the most effective eradication because all treatment units (trees) have died. In terms of the length of time for each treatment unit, it takes respectively around 10-15 minutes, 6-8 minutes, 4-5 minutes, and 2-3 minutes each for skin stripping treatment, felling with basting, felling, and direct removal. Based on the results of the study, it is recommended that the most effective application of A. crassicarpa eradication be carried out by a combination felling technique with basting.