Transformation of Cassava Peel into Nata de Cassava and Compost Biostarter in Jatipuro District Karanganyar. The Women Farmer Group (WFG) of Tani Waras V in Jatisobo Village and WFG Makmur in Jatimulyo Village of Jatipuro District have taken advantage of the abundance of cassava by processing it into rengginang and mocaf. The peel of cassava which reaches 10% of the wet weight of the cassava is the main waste in these productions. The purpose of this community service activity was to transfer the technology innovation to turn the cassava peel into "nata de cassava" and "compost biostarter" to the 2 WFGs. The service activity consisted of 2 phases. Phase I was the formulation of nata de cassava recipes, isolation of decomposer microbes from cassava peel for biostarter compost, and preparation of materials to be demonstrated to WFGs. Phase II was carried out with partners (1) delivering principal knowledge and technology, demonstrating the procedure of making nata de cassava and preparing compost biostarter (2) harvesting nata and isolates of decomposer microbes, and (3) application of compost biostarter. The evaluation results showed that the WFG members were very enthusiastic, as indicated by 90-95% of the members actively participated in all activities. They had performed the whole procedure of making nata (100%), moreover they were able to develop various recipes including using other waste materials with a success rate of 90-95%. The economic profit per recipe for nata fermentation media was estimated at Rp 51,500. Participants in the service activity also deepened their understanding and ability in the propagation of compost biostarter to produce healthy organic fertilizers.