Chitosan has the potential as a biostimulant also as an antagonistic agent due to its antimicrobial activity. These dual benefits were the superiority of chitosan and has the potential to be developed further. The objective of this study was to analyze the effect of soluble liquid (SL) chitosan on plant growth and the yield of curly chili. The study was conducted from April-August 2019 in Prambon Subdistrict, Nganjuk District, East Java. The total experimental plot was 2.000 m2 rows with 45 x 70 cm plant spacing. The variety of curly chili used was Kribo with three treatments examined i.e., the application of single chitosan SL (P1), the combination of chitosan SL and synthetic pesticide (P2), and the conventional application of synthetic pesticide that considered as control (K). Each treatment was replicated four times. The application of chitosan SL was conducted at 21, 42, and 63 days after planting (DAP) by foliar spray. The result showed that the application of chitosan SL increased the canopy width by 16,34% and plant height by 11,53% against control at 99 DAP. The number of fruits per plant also increased by 123% on P1 and 20% on P2 treatment. The fruit weight was also increased by 42,6% on P2 and 18% on P1 treatment. The conversion result showed that single chitosan SL application was able to increase the production of curly chili per hectare up to 163%, while the combination of chitosan SL and synthetic pesticide resulted up to 71% increase in curly chili production compared to control. Chitosan has the potential as a biostimulant also as an antagonistic agent due to its antimicrobial activity. These dual benefits were the superiority of chitosan and potentially to be developed further. The objective of this study was to analyze the effect of soluble liquid (SL) chitosan on the growth and yield of curly chili. The variety of curly chili used was Kribo with three treatments examined i.e. the application of single chitosan SL (P1), the combination of chitosan SL and synthetic pesticide (P2), and the conventional application of synthetic pesticide that considered as control (K). Each treatment was replicated four times. The application of chitosan SL was conducted at 21, 42, and 63 days after planting (DAP), while the application of synthetic pesticide was conducted depending on the field conditions. The plant parameters observed were canopy width, plant height, leaf color, and number, and weight of fruits. The observation results were analyzed using table of variance. The results showed that the application of chitosan SL increased the canopy width by 16.3% and plant height by 11.5% compared to control at 99 DAP. The number of fruits per plant also increased by 123% on P1 and 20% on P2 treatment. The fruit weight was also increased by 42.6% on P2 and 18% on P1 treatment. The conversion result showed that single chitosan SL application was able to increase the yield of curly chili per hectare up to 163%, while the combination of chitosan SL and synthetic pesticide resulted in 71% increase in curly chili yield compared to the control.[Keywords: antagonistic agent, biostimulant, chili var. Kribo, production, soluble liquid] Abstrakmikroba. Kedua manfaat ini yang menjadi keunggulan kitosan dan berpotensi untuk dikembangkan lebih lanjut. Penelitian ini bertujuan untuk menganalisis pengaruh aplikasi kitosan soluble liquid (SL) terhadap pertumbuhan dan hasil panen tanaman cabai keriting. Varietas cabai keriting yang digunakan adalah Kribo dengan tiga perlakuan yang diuji, yakni aplikasi kitosan SL tunggal (P1), kombinasi kitosan SL dengan pestisida sintetik (P2) dan aplikasi pestisida sintetik secara konvensional sebagai kontrol (K). Masing-masing perlakuan diulang empat kali. Aplikasi kitosan SL dilakukan pada umur tanaman 21, 42 dan 63 hari setelah tanam (HST), sedangkan aplikasi pestisida sintetik dilakukan berdasarkan kondisi di lapangan. Parameter tanaman yang diamati antara lain lebar kanopi, tinggi tanaman, warna daun, serta jumlah, dan berat buah. Hasil pengamatan dianalisis menggunakan tabel sidik ragam. Hasil penelitian menunjukkan bahwa aplikasi kitosan SL mampu meningkatkan lebar kanopi dan tinggi tanaman sebesar 16,3% dan 11,5% terhadap kontrol pada umur tanaman 99 HST. Jumlah buah per tanaman juga mengalami kenaikan sebesar 123% pada perlakuan P1 dan 20% pada perlakuan P2. Berat per buah mengalami kenaikan sebesar 42,6% pada perlakuan P2 dan 18% pada perlakuan P1. Hasil konversi menunjukkan bahwa aplikasi kitosan SL tunggal mampu meningkatkan produksi cabai keriting per hektar hingga 163%, sedangkan aplikasi kombinasi kitosan SL dan pestisida sintetik meningkatkan produksi sebesar 71% dibandingkan kontrol.[Kata kunci: agen antagonis, biostimulan, cabai var. Kribo, produksi, soluble liquid]